(s)-n-methylnaltrexone

ABSTRACT

This invention relates to S-MNTX, methods of producing S-MNTX, pharmaceutical preparations comprising S-MNTX and methods for their use.

RELATED APPLICATION

This application is a divisional of U.S. application Ser. No. 11/441,452filed on May 25, 2006, now pending, which claims benefit under 35 U.S.C.119(e) of the filing date of US Provisional Application Ser. No.60/684,570, filed on May 25, 2005, the entire disclosure of which isincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to (S)-N-methylnaltrexone (S-MNTX),stereoselective synthetic methods for the preparation of S-MNTX,pharmaceutical preparations comprising S-MNTX and methods for their use.

BACKGROUND OF INVENTION

Methylnaltrexone (MNTX) is a quaternary derivative of the pure opioidantagonist, naltrexone. It exists as a salt. Names used for the bromidesalt of MNTX in the literature include: Methylnaltrexone bromide;N-Methylnaltrexone bromide; Naltrexone methobromide; Naltrexone methylbromide; MRZ 2663BR. MNTX was first reported in the mid-70s by Goldberget al as described in U.S. Pat. No. 4,176,186. It is believed thataddition of the methyl group to the ring nitrogen forms a chargedcompound with greater polarity and less liposolubility than naltrexone.This feature of MNTX prevents it from crossing the blood-brain barrierin humans. As a consequence, MNTX exerts its effects in the peripheryrather than in the central nervous system with the advantage that itdoes not counteract the analgesic effects of opioids on the centralnervous system.

MNTX is a chiral molecule and the quaternary nitrogen can be in R or Sconfiguration. (See FIG. 1.) It is unknown whether the differentstereoisomers of MNTX exhibit different biological and chemicalproperties. All of the reported functions of MNTX described in theliterature indicate that MNTX is a peripheral opioid antagonist. Some ofthese antagonist functions are described in U.S. Pat. Nos. 4,176,186,4,719,215, 4,861,781, 5,102,887, 5,972,954, 6,274,591, 6,559,158, and6,608,075, and in U.S. patent application Ser. No. 10/163,482(2003/0022909A1), Ser. No. 10/821,811 (20040266806), Ser. No. 10/821,813(20040259899) and Ser. No. 10/821,809 (20050004155). These uses includereducing the side-effects of opioids without reducing the analgesiceffect of opioids. Such side-effects include nausea, emesis, dysphoria,pruritus, urinary retention, bowel hypomotility, constipation, gastrichypomotility, delayed gastric emptying and immune suppression. The artdiscloses that MNTX not only reduces the side-effects stemming fromopioid analgesic treatment but also reduces the side-effects mediated byendogenous opioids alone or in conjunction with exogenous opioidtreatment. Such side-effects include inhibition of gastrointestinalmotility, post-operative gastrointestinal dysfunction, idiopathicconstipation and other such conditions including, but not limited to,those mentioned above. However, it is unclear from the art whether theMNTX used in these studies was a mixture of R and S stereoisomers or asingle stereoisomer.

The art suggests that isolated stereoisomers of a compound sometimes mayhave contrasting physical and functional properties, although it isunpredictable whether this is the case in any particular circumstance.Dextromethorphan is a cough suppressant, whereas its enantiomer,levomethorphan, is a potent narcotic. R,R-methylphenidate is a drug totreat attention deficit hyperactivity disorder (ADHD), whereas itsenantiomer, S,S-methylphenidate is an antidepressant. S-fluoxetine isactive against migraine, whereas its enantiomer, R-fluoxetine is used totreat depression. The S enantiomer of citalopram is therapeuticallyactive isomer for treatment of depression. The R enantiomer is inactive.The S enantiomer of omeprazole is more potent for the treatment ofheartburn than the R enantiomer.

Bianchetti et al, 1983 Life Science 33 (Sup I):415-418 studied threepairs of diastereoisomers of quaternary narcotic antagonist and theirparent tertiary amines, levallorphan, nalorphine, and naloxone, to seehow the configuration about the chiral nitrogen affected in vitro and invivo activity. It was found that the activity varied considerablydepending on how the quaternary derivatives were prepared. In eachseries, only the diastereomer obtained by methylation of theN-allyl-substituted tertiary amine (referred to as “N-methyldiastereomer”) was potent in displacing ³H-naltrexone from rat brainmembranes, and acting as a morphine antagonist in the guinea-pig ileum.Conversely, diastereoisomers obtained by reacting N-methyl-substitutedtertiary amines with allyl halide (referred to as “N-allyldiastereomers”) did not displace 3H-naltrexone and had negligibleantagonist activity and slight agonist action in the guinea-pig ileum.In vivo findings were generally consistent with those in vitro. Thusonly the “N-methyl” but not the “N-allyl diastereomers” inhibitedmorphine-induced constipation in rats and behaved as antagonists. Theauthor stated that the prepared materials appeared to be pure by ¹H and¹³C nuclear magnetic resonance (NMR) analysis, but these methods are notaccurate. The author cites a literature reference for the assignment ofthe R configuration to the “N-methyl diastereomer” of nalorphine. Noassignment is proposed for the levallorphan and naloxone diastereomers.It would be adventurous to extrapolate the configuration to thesediastereomers (R. J. Kobylecki et al, J. Med. Chem. 25, 1278-1280,1982).

Goldberg et al.'s U.S. Pat. No. 4,176,186, and more recently Cantrell etal.'s WO 2004/043964 A2 describe a protocol for the synthesis of MNTX.Both describe a synthesis of MNTX by quaternizing a tertiaryN-substituted morphinan alkaloid with a methylating agent. Both Goldberget al. and Cantrell et al. are silent as to the stereoisomer(s) producedby the synthesis. The authors remained cautiously silent about thestereochemistry because the stereochemistry could not be determinedbased on prior art. The cyclopropylmethyl side-chain in naltrexone isdifferent from the prior art side-chains and may have affected thestereochemical outcome in the synthesis of MNTX, as may other reactionparameters such as temperature and pressure. Based on the method ofsynthesis described in each, it is unknown whether the MNTX so producedwas R, S or a mixture of both.

S-MNTX in pure form, and a method of making pure S-MNTX have not beendescribed in the literature. Researchers would have been unable todefinitively characterize and distinguish the stereoisomer(s) obtainedby the. Goldberg et al. or Cantrell et al. synthesis-in the absence ofS-MNTX as a standard.

SUMMARY OF THE INVENTION

S-MNTX has now been produced in high purity, permitting thecharacterization of its relative retention time in chromatography versusthat of (R)-N-methylnaltrexone (R-MNTX). S-MNTX has been found to haveactivity different from the activity of MNTX reported in the literature.

The present invention provides highly pure S-MNTX, crystals of highlypure S-MNTX and intermediates thereof, novel methods for making highlypure S-MNTX, methods for analyzing S-MNTX in a mixture of R-MNTX andS-MNTX, methods of distinguishing R-MNTX from S-MNTX, methods ofquantifying S-MNTX, pharmaceutical products containing the same andrelated uses of these materials.

S-MNTX, and salts thereof are provided. A protocol for obtaining S-MNTXwas unpredictable from the prior art. In addition, it has beendiscovered, surprisingly, that S-MNTX has opioid agonist activity.

According to one aspect of the invention, a composition is provided. Thecomposition is an isolated compound of the S configuration with respectto nitrogen of Formula I:

to wherein X is a counterion.

S-MNTX is a salt. Therefore, there will be a counterion, which for thepresent application, includes the zwitterion. More typically, thecounterion is a halide, sulfate, phosphate, nitrate, or anionic-chargedorganic species. Halides include fluoride, chloride, iodide and bromide.In some important embodiments, the halide is iodide and in otherimportant embodiments the halide is bromide. In some embodiments theanionic-charged species is a sulfonate or a carboxylate. Examples ofsulfonates include mesylate, besylate, tosylate, and triflate. Examplesof carboxylates include formate, acetate, citrate, and fumarate.

According to the invention, S-MNTX is provided in isolated form. Byisolated, it is meant at least 50% pure. In important embodiments,S-MNTX is provided at 75% purity, at 90% purity, at 95% purity, at 98%purity, and even at 99% purity or above. In one important embodiment,the. S-MNTX is in a crystal form.

According to another aspect of the invention, a composition is provided.The composition is MNTX, wherein the MNTX present in the composition isgreater than 10% in S configuration with respect to nitrogen. Morepreferably, the MNTX present in the composition is greater than 30%,40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 98.5%, 99%,99.5%, 99.6%, 99.7%, 99.8%, and even 99.9% in S configuration withrespect to nitrogen. In some embodiments there is no detectable R-MNTXas measured by high performance liquid chromatography (HPLC).

The composition in some embodiments is a solution, in others an oil, inothers a cream, and in still others a solid or semi-solid. In oneimportant embodiment, the composition is a crystal.

According to another aspect of the invention, a pharmaceuticalpreparation is provided. The pharmaceutical preparation includes any oneof the compositions of S-MNTX described above in a pharmaceuticallyacceptable carrier. The pharmaceutical preparation contains a effectiveamount of S-MNTX. In some embodiments, there is little or no detectableR-MNTX in the composition. If present, R-MNTX is at a level such thateffective amounts of S-MNTX are administered to a subject. In someembodiments, the pharmaceutical preparation further includes atherapeutic agent other than MNTX. In one embodiment, the therapeuticagent is an opioid or opioid agonist. Examples of opioids or opioidagonists are alfentanil, anileridine, asimadoline, bremazocine,burprenorphine, butorphanol, codeine, dezocine, diacetylmorphine(heroin), dihydrocodeine, diphenoxylate, fedotozine, fentanyl,funaltrexamine, hydrocodone, hydromorphone, levallorphan, levomethadylacetate, levorphanol, loperamide, meperidine (pethidine), methadone,morphine, morphine-6-glucuronide, nalbuphine, nalorphine, opium,oxycodone, oxymorphone, pentazocine, propiram, propoxyphene,remifentanyl, sufentanil, tilidine, trimebutine, tramadol, orcombinations thereof. In some embodiments, the opioid or opioid agonistdoes not readily cross the blood brain barrier and, therefore, hassubstantially no central nervous system (CNS) activity when administeredsystemically (i.e., it is of the class of agents known as “peripherallyacting”) agents. In other embodiments the therapeutic agent is an opioidantagonist. Opioid antagonists include peripheral mu opioid antagonists.Examples of peripheral mu opioid antagonists include quarternaryderivatives of noroxymorphone (See Goldberg et al, U.S. Pat. No.4,176,186, and Cantrell et al WO 2004/043964), piperidineN-alkylcarboxylates such as described in U.S. Pat. Nos. 5,250,542;5,434,171; 5,159,081; 5,270,328; and 6,469,030, opium alkaloidderivatives such as described in U.S. Pat. Nos. 4,730,048; 4,806,556;and 6,469,030, quaternary benzomorphan compounds such as described inU.S. patents 3,723,440 and 6,469,030.

In one embodiment, the peripheral opioid antagonist is R-MNTX. R-MNTX isthe predominant form of MNTX following the manufacturing proceduresdescribed in the prior art, although it is believed that suchpreparations are contaminated with S-MNTX. Pure R-MNTX can besynthesized using the following protocol. In brief, stereoselectivesynthesis of R-MNTX is carried out by adding a hydroxyl protecting groupto naltrexone to yield 3-O-protected-naltrexone; methylating the3-O-protected-s naltrexone to yield 3-O-protected-R-MNTX salt; andremoving hydroxyl protecting group to yield R-MNTX. The hydroxylprotecting group can be added in the presence of each or both: anorganic solvent, e.g. tetrahydrofuran, and/or a tertiary amine that isnot naltrexone, e.g. triethylamine. The naltrexone can be methylated byreacting the 3-O-protected-naltrexone with methyl iodide to produce3-O-protected-R-MNTX iodide salt. Naltrexone can be protected by ahydroxyl protecting group such as isobutyryl. The 3-O-protected-R-MNTXiodid e salt can be treated with hydrobromic acid to remove theprotecting group and produce R-MNTX bromide/iodide salt, and thebromide/iodide salt can be passed through an anion exchange resin column(bromide form) to yield R-MNTX bromide.

In other embodiments, the therapeutic agent is not an opioid, opioidagonist, or an opioid antagonist. For example, the therapeutic agent canbe an antiviral agent, antibiotic agent, antifungal agent, antibacterialagent, antiseptic agent, anti-protozoal agent, anti-parasitic agent,anti-inflammatory agent, a vasoconstrictor agent, a local anestheticagent, an anti-diarrheal agent, an anti-hyperalgesia agent, orcombinations thereof.

In one aspect of the invention, the S-MNTX is combined with ananti-diarrhea agent that is loperamide, loperamide analogs, N-oxides ofloperamide and analogs, metabolites and prodrugs thereof, diphenoxylate,cisapride, antacids, aluminum hydroxide, magnesium aluminum silicate,magnesium carbonate, magnesium hydroxide, calcium carbonate,polycarbophil, simethicone, hyoscyamine, atropine, furazolidone,difenoxin, octreotide, lansoprazole, kaolin, pectin, activated charcoal,sulphaguanidine, succinylsulphathiazole, phthalylsulphathiazole, bismuthalurninate, bismuth subcarbonate, bismuth subcitrate, bismuth citrate,tripotassium dicitrato bismuthate, bismuth tartrate, bismuthsubsalicylate, bismuth subnitrate and bismuth subgallate, opium tincture(paregoric), herbal medicines, plant-derived anti-diarrheal agents orcombinations thereof.

In one aspect of the invention, the S-MNTX is combined with ananti-inflammatory agent that is a non-steroidal anti-inflammatory drug(NSAID), a tumor necrosis factor inhibitor, basiliximab, daclizumab,infliximab, mycophenolate, mofetil, azothioprine, tacrolimus, steroids,sulfasalazine, olsalazine, mesalamine, or combinations thereof.

The pharmaceutical preparations of the invention can take on a varietyof forms, including, but not limited to a composition that is entericcoated, a composition that is a controlled release or sustained releaseformulation, a composition that is a solution, a composition that is atopical formulation, a composition that is a suppository, a compositionthat is lyophilized, a composition that is in an inhaler, a compositionthat is in a nasal spray device, and the like. The composition can befor oral administration, parenteral administration, mucosaladministration, nasal administration, topical administration, ocularadministration, local administration, etc. If parenteral, theadministration can be subcutaneous, intravenous, intradermal,intraperitoneal, intrathecal, etc.

According to another aspect of the invention, a method for synthesizingS-MNTX salt is provided. The method involves combining (iodomethyl)cyclopropane with oxymorphone in a first solvent to produce an iodo saltof S-MNTX. Counterions then may be substituted, optionally, for iodideby transferring the iodo salt S-MNTX to a second solvent and exchangingiodide for a counterion other than iodide. In one important embodiment,the iodo salt of S-MNTX is transferred from the first solvent to asecond solvent, and the iodide is exchanged in the second solvent forbromide to produce a bromo salt of S-MNTX. The preferred first solventis a dipolar aprotic solvent. Most preferred is N-methylpyrrolidone(NMP). The preferred second solvent is at least isopropyl acetate ordioxane. The method of the invention also involves purifying the salt ofS-MNTX by chromatography, recrystallization, or a combination thereof Inone embodiment, the purification is by multiple recrystallizations. Thereaction can be carried out across a wide temperature spectrum and atatmospheric conditions. In important embodiments, the reaction in thefirst solvent is conducted under a controlled reaction temperaturebetween 65° to 75° C., preferable at about 70° C., and the reaction inthe second solvent is conducted at room temperature.

More broadly, the method involves synthesizing S-MNTX plus counterion bycombining a cyclopropylmethyl derivative with oxymorphone in a firstsolvent to produce the S-MNTX plus counterion. The cyclopropylmethylderivative contains a leaving group. Preferably the leaving group is ahalide or sulfonate . Preferably the leaving group is iodide. The firstsolvent may be a dipolar aprotic solvent. Examples of such solvents areN-methylpyrrolidone, dimethyl formamide, methylphosphoramide, acetone,1,4-dioxane, and acetonitrile and combinations thereof. Preferred isN-methylpyrrolidone. The first solvent can be a dipolar protic solvent.Examples are 2-propanol, 1-propanol, ethanol, methanol. The method canfurther involve exchanging the counterion of S-MNTX with anothercounterion. Examples of counterions are bromide, chloride, fluoride,nitrate, sulfonate, or carboxylate. The sulfonate can be mesylate,besylate, tosylate or triflate. The carboxylate can be formate, acetate,citrate and fumarate. The method can involve transferring the S-MNTXcounterion to a second solvent prior to exchanging the counterion ofS-MNTX with another counterion. The method can further involve purifyingthe S-MNTX plus counterion, for example by recrystallization, bychromatography or by both.

According to another aspect of the invention, method is provided forinhibiting diarrhea in a subject, by administering to a subject in needof such treatment a pharmaceutical composition containing S-MNTX in anamount effective to treat or prevent the diarrhea. The pharmaceuticalpreparation can be of the type described above. The diarrhea can beacute or chronic. The diarrhea can be caused by any variety ofcircumstances, alone or combined, such as caused by an infectious agent,food intolerance, food allergy, malabsorption syndrome, reaction to amedication or nonspecific etiology. In some embodiments, the diarrhea isassociated with irritable bowel disease or with inflammatory boweldisease. In one embodiment the inflammatory bowel disease is celiacdisease. In another embodiment the inflammatory bowel disease is Crohn'sdisease. In yet another embodiment, the inflammatory bowel disease isulcerative colitis. In other embodiments the diarrhea results fromstomach or bowel resection, removal of a gall bladder, or organiclesions. In other embodiments, the diarrhea is associated with acarcinoid tumor or vasoactive intestinal polypeptide-secreting tumor. Instill other embodiments, the diarrhea is chronic functional (idiopathic)diarrhea.

According to the invention, the S-MNTX may be administered inconjunction with an anti-diarrhea agent that is not S-MNTX. By inconjunction with, it is meant at the same time or close enough in timewhereby both agents are treating the condition at the same time. In oneembodiment, the agent is an opioid or an opioid agonist. In anotherembodiment, the agent is not an opioid or an opioid agonist.

According to another aspect of the invention, a method is provided forreducing a volume of discharge from a ileostomy or cholostomy in asubject. The method involves administering to a subject in need of suchreduction a pharmaceutical composition containing S-MNTX in an amounteffective to reduce the volume of discharge from the ileostomy orcholostomy. The pharmaceutical preparation can be of the type describedabove.

According to another aspect of the invention, a method is provided forreducing a rate of discharge from a ileostomy or cholostomy in asubject. The method involves administering to a subject in need of suchreduction a pharmaceutical composition containing S-MNTX in an amounteffective to reduce the rate of discharge from the ileostomy orcholostomy. The pharmaceutical preparation can be of the type describedabove.

According to another aspect of the invention, a method is provided forinhibiting gastrointestinal motility in a subject. The method involvesadministering to a subject in need of such inhibition a pharmaceuticalcomposition containing S-MNTX in an amount effective to inhibitgastrointestinal motility in the subject. The pharmaceutical preparationcan be of the type described above. According to the invention, theS-MNTX may be administered in conjunction with another motilityinhibiting agent that is not S-MNTX. In one embodiment, the agent is anopioid or an opioid agonist. Opioids and opioid agonists are describedabove. In another embodiment, the agent is not an opioid or an opioidagonist. Examples of such gastrointestinal motility inhibiting agentsare described below, each as if recited specifically in this summary ofinvention.

According to another aspect of the invention, a method is provided fortreating irritable bowel syndrome. The method involves administering toa patient in need of such treatment a pharmaceutical compositioncontaining S-MNTX in an amount effective to ameliorate at least onesymptom of the irritable bowel syndrome. The pharmaceutical preparationcan be of the type described above. In one embodiment, the symptom isdiarrhea. In another embodiment, the symptom is alternating constipationand diarrhea. In another embodiment, the symptom is abdominal pain,abdominal bloating, abnormal stool frequency, abnormal stoolconsistency, or combinations thereof.

According to another aspect of the invention, a method is provided forinhibiting pain in a subject. The method involves administering to apatient in need of such treatment a pharmaceutical compositioncontaining S-MNTX in an amount effective to inhibit the pain. Thepharmaceutical preparation can be of the type described above. Themethod can further involve administering to the subject a therapeuticagent other than S-MNTX. In one embodiment the agent other than S-MNTXis an opioid. In another embodiment, the agent other than S-MNTX is anonopioid pain relieving agent. Nonopioid pain relieving agents includecorticosteroids and nonsteroidal anti-inflammatory drugs. Pain relievingagents are described in greater detail below, as if recited herein thissummary. In another embodiment, the agent other than S-MNTX is anantiviral agent, antibiotic agent, antifungal agent, antibacterialagent, antiseptic agent, anti-protozoal agent, anti-parasitic agent,anti-inflammatory agent, a vasoconstrictor agent, a local anestheticagent, an anti-diarrheal agent, or an anti-hyperalgesia agent. If thepain is peripheral hyperalgesia, it can result, for example, from abite, sting, burn, viral or bacterial infection, oral surgery, toothextraction, injury to the skin and flesh, wound, abrasion, contusion,surgical incision, sunburn, rash, skin ulcers, mucositis, gingivitis,bronchitis, laryngitis, sore throat, shingles, fungal irritation, feverblisters, boils, plantar's warts, vaginal lesions, anal lesions, cornealabrasion, post-radial keratectomy, or inflammation. It also can beassociated with post-surgery recovery. The surgery can be, for example,radial keratectomy, tooth extraction, lumpectomy, episiotomy,laparoscopy, and arthroscopy.

In some embodiments, the pharmaceutical composition is administeredlocally to a site of the pain. In some embodiments, the administrationis intra-articular. In some embodiments, the administration is systemic.In some embodiments, the administration is topical. In some embodiments,the composition is administered to the eye.

According to another aspect of the invention, a method is provided forinhibiting inflammation in a subject. The method involves administeringto a patient in need of such treatment a pharmaceutical compositioncontaining S-MNTX in an amount effective to inhibit the inflammation.The pharmaceutical preparation can be of the type described above. Themethod can also involve administering to the subject a therapeutic agentother than S-MNTX. The therapeutic agent other than S-MNTX can be ananti-inflammatory agent. The administration can be, for example, localadministration at a site of the inflammation, systemic administration,or topical administration.

The inflammation in some embodiments is periodontal inflammation,orthodontic inflammation, inflammatory conjunctivitis, hemorrhoids andvenereal inflammations. In other embodiments, the inflammation is a skininflammatory condition. Examples include inflammation associated with adisorder selected from the group consisting of irritant contactdermatitis, psoriasis, eczema, pruritus, seborrheic dermatitis, nummulardermatitis, lichen planus, acne vulgaris, comedones, polymorphs,nodulokystic acne, conglobata, senile acne, secondary acne, medicalacne, a keratinization disorder, and blistery derma, atopic dermatitis,and UV-induced inflammation . The skin inflammatory condition also canbe associated with skin sensitizatiorior irritation arising from the useof a cosmetic or skin care product which causes skin sensitization orirritation or can be a non-allergic inflammatory skin condition. It alsocan be induced by all-trans-retinoic acid. In other embodiments, theinflammation can be a systemic inflammatory condition. Examples includeconditions selected from the group consisting of inflammatory boweldisease, rheumatoid arthritis, cachexia, asthma, Crohn's disease,endotoxin shock, adult respiratory distress syndrome,ischemic/reperfusion damage, graft-versus-host reactions, boneresorption, transplantation and lupus. Other embodiments can involveinflammation associated with a. condition selected from the groupconsisting of multiple sclerosis, diabetes, and wasting associated withacquired immunodeficiency syndrome (AIDS) or cancer.

According to another aspect of the invention, a method is provided forinhibiting the production of tumor necrosis factor in a subject. Themethod involves administering to a patient in need of such treatment apharmaceutical composition containing S-MNTX in an amount effective toinhibit the production of tumor necrosis factor. The pharmaceuticalpreparation can be of the type described above. The method can alsoinvolve administering to the subject a therapeutic agent other thanS-MNTX.

According to another aspect of the invention, a method is provided forregulating gastrointestinal function in a subject. The method involvesadministering to a patient in need of such treatment a pharmaceuticalcomposition containing S-MNTX and administering to the subject aperipheral mu opioid antagonist, both in amounts to regulategastrointestinal function. In one embodiment, the peripheral mu opioidantagonist is R-MNTX.

According to another aspect of the invention, a method is provided. Themethod involves preventing or treating a psychogenic eating or digestivedisorder by administering to a patient a composition described above inan amount effective to prevent or treat the psychogenic eating ordigestive disorder.

According to another aspect of the invention, a kit is provided. The kitincludes a package containing a sealed container of a pharmaceuticalcomposition containing S-MNTX. The kit further can include a therapeuticagent other than S-MNTX. The therapeutic agent other than S-MNTX in oneembodiment is an opioid or opioid agonist. In one aspect, the opioid oropioid agonist has substantially no CNS activity when administeredsystemically (i.e., is “peripherally acting”). In other embodiments, thetherapeutic agent other than S-MNTX is an opioid antagonist. Opioidantagonists include peripheral mu opioid antagonists. In one embodiment,the peripheral opioid antagonist is R-MNTX. In other embodiments, theagent other than S-MNTX is an antiviral agent, antibiotic agent,antifungal agent, antibacterial agent, antiseptic agent, anti-protozoalagent, anti-parasitic agent, anti-inflammatory agent, a vasoconstrictoragent, a local anesthetic agent, an anti-diarrheal agent, or ananti-hyperalgesia agent, or combinations thereof.

According to another aspect of the invention, a method for analyzingS-MNTX in a mixture of R-MNTX and S-MNTX is provided. The methodinvolves conducting high performance liquid chromatography (HPLC) andapplying S-MNTX to the chromatography column as a standard. The methodpreferably involves applying both S-MNTX and R-MNTX as standards todetermine relative retention/elution times. Relative Retention times ofR and S-MNTX are disclosed therein. In one aspect of this invention, thechromatography is conducted using two solvents, solvent A and solvent B,wherein solvent A is an aqueous solvent and solvent B is a methanolicsolvent and wherein both A and B contain trifluroacetic acid (TFA).Preferably, A is 0.1% aqueous TFA and B is 0.1% methanolic TFA. Inimportant embodiments the column comprises a bonded, end-capped silica.In important embodiments, the pore size of the column gel is 5 microns.In a most preferred embodiment, the column, flow rate and gradientprogram are as follows:

-   Column: Luna C18(2), 150×4.6 mm, 5μ-   Flow Rate: 1 mL/min-   Gradient Program:

Time (min) % A % B  0:00 95 5  8:00 65 35 12:00 35 65 15:00 0 100 16:0095 5 18:00 95 5Detection can be carried out conveniently by ultraviolet (UV) @ 230 nmwavelength.The foregoing HPLC also can be used to determine the relative amount ofS-MNTX and R-MNTX by determining the area under the respective R and Scurves in the chromatogram produced.

According to another aspect of the invention, methods are provided forensuring the manufacture of S-MNTX (which is an opioid agonist) that isfree of R-MNTX (which is an opioid antagonist). The methods permit forthe first time the assurance that a pharmaceutical preparation of S-MNTXwhich is intended for agonist activity is not contaminated with acompound that opposes the activity of S-MNTX. In this aspect of theinvention, a method is provided for manufacturing S-MNTX. The methodinvolves: (a) obtaining a first composition containing S-MNTX, (b)purifying the first composition by chromatography, recrystallization ora combination thereof, (c) conducting HPLC on a sample of purified firstcomposition using R-MNTX as a standard, and (d) determining the presenceor absence of R-MNTX in the sample. In important embodiments, bothR-MNTX and S-MNTX are used as standards to determine, for example,relative retention time of R-MNTX and S-MNTX. In one embodiment, thepurifying is multiple recryallization steps or multiple chromatographysteps. In another embodiment, the purifying is carried out until R-MNTXis absent from the sample as determined by HPLC. It should beunderstood, however, that the “purified first composition” in someaspects of the invention is not necessarily free of detectable R-MNTX.The presence of such R-MNTX, for example, might indicate that furtherpruification steps should be conducted if pure S-MNTX is desired. Themethods can further involve packaging purified first composition that isfree of HPLC detectable R-MNTX. The methods further can includeproviding indicia on or within the packaged, purified first compositionindicating that the packaged, purified first composition is free of HPLCdetectable R-MNTX. The method further can involve packaging apharmaceutically effective amount for treating anyone of the conditionsdescribed herein. The first composition containing S-MNTX can beobtained by the methods described herein. Pure R-MNTX can be obtained asdescribed herein.

According to another aspect of the invention, a packaged product isprovided. The package contains a composition comprising S-MNTX, whereinthe composition is free of HPLC detectable R-MNTX, and indicia on orcontained within the package indicating that the composition is free ofdetectable R-MNTX. The composition can take on a variety of forms,including, but not limited to, a standard for use in laboratoryexperiments, a standard for use in manufacturing protocols, or apharmaceutical composition. If the composition is a pharmaceuticalcomposition, then one important form of indicia is writing on a label orpackage insert describing the characteristics of the pharmaceuticalpreparation. The indicia can indicate directly that the composition isfree of R-MNTX, or it can indicate the same indirectly, by stating forexample that the composition is pure or 100% S-MNTX. The pharmaceuticalcomposition can be for treating any of the conditions described herein.The pharmaceutical composition can contain an effective amount of thepure S-MNTX and can take any of the forms described below as ifspecifically recited in this summary, including, but not limited to,solutions, solids, semi-solids, enteric coated materials and the like.

These and other aspects of the invention are described in greater detailbelow.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 provides the chemical structure of bromide salts of R-MNTX andS-MNTX;

FIG. 2 illustrates a representative reaction scheme of the invention;

FIG. 3 provides a proton NMR spectrum of S-MNTX;

FIG. 4 provides an infrared spectrum of S-MNTX;

FIG. 5 provides an HPLC chromatogram of S-MNTX;

FIG. 6 provides a mass spectrogram of S-MNTX; and

FIG. 7 illustrates a kit according to the invention.

DETAILED DESCRIPTION

The invention provides for the compound, S-MNTX, synthetic routes forstereoselective synthesis of S-MNTX, substantially pure S-MNTX, crystalsof substantially pure S-MNTX, methods of analysis of S-MNTX,pharmaceutical preparations containing substantially pure S-MNTX, andmethods for their use.

S-MNTX, also called (S)-N-(cyclopropylmethyl)-noroxymorphone methyl salthas the structure in Formula I:

wherein X is a counterion. The counterion can be any counterion,including a zwitterion. Preferably the counterion is pharmaceuticallyacceptable. Counterions include halides, sulfates, phosphates, nitrates,and anionic-charged organic species. The halide can be iodide, bromide,chloride, fluoride, or combinations thereof. In one embodiment thehalide is iodide. In a preferred embodiment the halide is bromide. Theto anionic-charged organic species may be a sulfonate or carboxylate.

It is believed that the methods of manufacture and the agonistproperties of S-MNTX apply equally to S-quarternary derivatives ofnoroxymorphone other than where the derivative is cyclopropylmethyl.Thus, the invention is intended to embrace S-quartemary derivatives ofnoroxymorphone where the cyclopropylmethyl is replaced with a moiety R,where R is a 1-20 carbon hydrocarbyl consisting exclusively of carbonand hydrogen, including alkyl, alkenyl, alkynyl, and aryl, substitutedor unsubstituted with hydrocarbons or with one or more atoms such asnitrogen, oxygen, silicon, phosphorus, boron, sulfur, or halogen(described in PCT publication WO 2004/043964.) In important embodiments,R is allyl, chloroallyl, or propargyl. In important embodiments, thehydrocarbyl contains 4-10 carbons.

“Alkyl”, in general, refers to an aliphatic hydrocarbon group which maybe straight, branched or cyclic having from 1 to about 10 carbon atomsin the chain, and all combinations and subcombinations of rangestherein. “Branched” refers to an alkyl group in which a lower alkylgroup, such as methyl, ethyl or propyl, is attached to a linear alkylchain. In certain preferred embodiments, the alkyl group is a C₁-C₅alkyl group, i.e., a branched or linear alkyl group having from 1 toabout 5 carbons. In other preferred embodiments, the alkyl group is aC₁-C₃ alkyl group, i.e., a branched or linear alkyl group having from 1to about 3 carbons. Exemplary alkyl groups include methyl, ethyl,n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl,hexyl, heptyl, octyl, nonyl and decyl. “Lower alkyl” refers to an alkylgroup having 1 to about 6 carbon atoms. Preferred alkyl groups includethe lower alkyl groups of 1 to about 3 carbons.

An “alkylating agent” is a compound that can be reacted with a startingmaterial to bind, typically covalently, an alkyl group to the startingmaterial. The alkylating agent typically includes a leaving group thatis separated from the alkyl group at the time of attachment to thestarting material. Leaving groups may be, for example, halogens,halogenated sulfonates or halogenated acetates. An example of analkylating agent is cyclopropylmethyl iodide.

“Organic solvent” has its common ordinary meaning to those of skill inthis art. Exemplary organic solvents useful in the invention include,but are not limited to tetrahydrofuran, acetone, hexane, ether,chloroform, acetic acid, acetonitrile, chloroform, cyclohexane,methanol, and toluene. Anhydrous organic solvents are included.

“Dipolar aprotic” solvents are protophilic solvents that cannot donatelabile hydrogen atoms and that exhibit a permanent dipole moment.Examples include acetone, ethyl acetate, dimethyl sulfoxide (DMSO),dimethyl formamide (DMF) and N-methylpyrrolidone.

“Dipolar protic” solvents are those that can donate labile hydrogenatoms and that exhibit a permanent dipole moment. Examples includewater, alcohols such as 2-propanol, ethanol, methanol, carboxylic acidssuch as formic acid, acetic acid, and propionic acid.

S-MNTX exhibits properties different from those of R-MNTX and differentproperties from a mixture of S- and R- MNTX. Those properties includemobility on chromatography columns, biological and functional activity,and crystal structure. It is believed that the in vivo clearance rate,the side-effect profile, and the like may also differ from R-MNTX ormixtures of R-MNTX and S-MNTX. As discovered and claimed herein, pureS-MNTX behaves as an agonist of peripheral opioid receptors asdemonstrated by inhibition of gastrointestinal transit. As aconsequence, S-MNTX activity may be interfered with or antagonized byR-MNTX in mixtures containing both R-MNTX and S-MNTX. It therefore ishighly desirable to have S-MNTX in isolated and substantially pure form.

In one aspect of the invention, methods for the synthesis of S-MNTX areprovided. S-MNTX may be produced at a purity of greater than or equal to10%, 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 98%,98.5%, 99%, and 99.5% area under the curve (AUC) based onchromatographic techniques. In a preferred embodiment, the purity ofS-MNTX is 98% or greater. The amount of R-MNTX in the purified S-MNTXmay be less than or equal to about 90%, 80%, 70%, 60%, 50%, 40%, 30%,20%, 10%, 5%, 3%, 2%, 1%, 0.5%, 0.3%, 0.2%, 0.1% (AUC) or undetectableby chromatographic techniques described herein. It will be apprriciatedby the skilled artisan that the detection of the methods will dependupon the detection and quantitation limits of the employed technique.Quantitation Limit is the lowest amount of R-MNTX that can beconsistently measured and reported, regardless of variations inlaboratories, analysts, instruments or reagent lots. Detection Limit isthe lowest amount of R-MNTX in a sample which can be detected but notnecessarily quantitated as an exact value. In one embodiment of theinvention the detection limit is 0.1% and the quantitation limit is0.2%. In yet another embodiment the detection limit is 0.02% and thequantitation limit is 0.05%.

Various synthetic protocols were attempted to synthesize S-MNTX. Many ofthe syntheses failed to make S-MNTX or failed to make S-MNTX atacceptable purity levels or yields. In the successful method of theinvention, S-MNTX was synthesized via the direct alkylation ofoxymorphone while leaving the phenolic OH group of oxymorphoneunprotected (FIG. 2). Oxymorphone was reacted with themethylcyclopropane species iodomethyl cyclopropane. The S-MNTX salt thatresults includes a counterion such as iodide, that can then be exchangedfor a preferred counterion such as bromide. The starting material in thesynthesis of S-MNTX, oxymorphone, may be obtained at about 95% yieldthrough the demethylation of oxycodone, for example, with borontribromide. Alternatively, the oxymorphone may be obtained throughcommercial sources.

An alkylation reaction may be performed in a solvent, or solvent system,that may be anhydrous. The solvent system may be a single solvent or mayinclude a combination of two or more solvents. Suitable solvent systemsmay include dipolar aprotic solvents such as N-methylpyrrolidone (NMP),dimethyl formamide (DMF), hexamethylphosphoramide (HMPA), acetone,1,4-dioxane and acetonitrile, and dipolar protic solvents such as2-propanol. Solvent systems may also include dipolar aprotic solvents incombination with aliphatic ethers, such as tetrahydrofuran (THF),1,2-dimethoxyethane (glyme), diethyleneglycol-dimethyl ether (diglyme),1,4-dioxane, methyl t-butyl ether (methyl 1,1,-dimethylethyl ether, or2-methyl-2-methoxypropane)diethykl ether, other polar solvents may alsobe included in some embodiments. For instance, the solvent system mayinclude acetone, methylethylketone, diethylketone (3-pentanone), andt-butylmethylketone(3,3-dimethylbutan-2-one). Alkylation solvent systemsmay also include aliphatic or alicyclic congeners of any of thecompounds disclosed above. Solvent systems may include two or moresolvents in any proportion and appropriate proportions for a particularalkylation reaction may be determined through routine experimentation.Notwithstanding the foregoing, surprisingly, NMP proved the preferredsolvent.

The solvent may be used at a ratio of less than, greater than, or equalto about 1, 2, 3, 4, 5, 10 or more volumes. In some cases it may bepreferred to minimize the amount of solvent used, such as when productis to be transferred from the solvent using a liquid/liquid extractionor when product is to be crystallized or when the solvent is to beremoved from the product.

The alkylating agent may be added to the starting material in variousmolar ratios, such as less than 8, 12, 16, 20, 24 or greater than 24equivalents per equivalent of starting material. In some instances, ithas been found that reaction efficiency (production of S-MNTX) may besubstantially independent of the amount of alkylating agent used.

In one set of embodiments, alkylation may be performed using theFinkelstein reaction. An alkyl halide, such as cyclopropylmethylchloride, can be combined with a halide salt, such as sodium iodide, tocontinuously supply a reactive halogenated alkylating agent, such ascyclopropylmethyl iodide, that is replenished as it is consumed.

Starting materials may be alkylated at atmospheric pressure in an openvessel or under pressure. The reaction is conducted such that thetemperature is maintained or controlled over the reaction time at aprescribed temperature using methods/equipment as are known in the art.One device for maintaining a controlled temperature throughout thealkylation reaction is a heater/chiller unit. Controlling thetemperature throughout the alkylation reaction inhibits or reducestemperature fluctuations. In one embodiment, the temperature does notexceed 110° C., preferably does not exceed 100° C. For example,oxymorphone may be alkylated in an open or closed vessel over a range offrom 50 to 100° C., 60 to 90° C., or 65 to 75° C. The reaction isallowed to proceed up to about 22 hours, preferably for about 15 to 22hours, more preferably about 16 to 20 hours. It is contemplated thatreaction times may be shortened through the use of microwaveirradiation. In one embodiment, reactants are placed in a closed vesselat 70° C. for about 17 hours to produce a product having a ratio ofoxymorphone to S-MNTX of about 1:1. In a preferred embodiment, thealkylation is conducted at 70° C. for about 20 hours in an open vessel(atmospheric pressure) wrapped to reduce exposure to light.

In some embodiments, S-MNTX may be isolated from the solvent in which itis produced. For example, the solvent may be removed from a residuecontaining the S-MNTX, or any. S-MNTX may be transferred from thealkylation solvent to a transfer solvent. Transfer solvents may be polaror non-polar and may have boiling points below 100° C. Transfer solventsmay include esters, aldehydes, ethers, alcohols, aliphatic hydrocarbons,aromatic hydrocarbons and halogenated hydrocarbons. Specific transfer tosolvents include, for example, dioxane, ethyl acetate, isopropylacetate, methanol, ethanol, dichloromethane, acetonitrile, water,aqueous HBr, heptane, and MTBE. In one embodiment, a mixture ofisopropyl acetate and dioxane can be used to at least partially isolateS-MNTX from NMP. Upon mixing one or more of these solvents with asolution of S-MNTX in NMP, a light colored solid may develop thatbecomes an oil over time.

Any residue obtained from the solvent may be worked up to purify andisolate the product, S-MNTX. Purification and isolation may be doneusing methods known to those skilled in the art, such as by usingseparation techniques like chromatography, recrystalization, orcombinations of various separation techniques as are known the art. Inone embodiment, flash chromatography using a C18 column may be used withan aqueous methanol solvent modified with 0.2% HBr. Methanol content mayvary from, for example, about 2.5% to about 50%. In a preferredembodiment, the S-MNTX is purified using recrystallization.The processmay be repeated until desired purity of product is obtained. In oneembodiment, S-MNTX is recrystallized at least two times, three times, orfour or more times to achieve the desired level of purity. For example,S-MNTX may be obtained at purities of greater than or equal to 50%, 80%,85%, 90%, 95%, 97%, 98% , 98.5%, 99.8% (AUC) based on chromatographictechniques. Any impurities may include the starting material,oxymorphone of less than 0.2%, with no detectable R-MNTX.Recrystallization may be achieved using a single solvent, or acombination of solvents. A preferred recrystallization is achieved bydissolving S-MNTX in a polar solvent, and then adding a less polarcosolvent. In a more preferred embodiment, S-MNTX is purified byrecrystallization from methanol and the cosolvent CH₂Cl₂/IPA (6:1). Therecrystallization is repeated to achieve desired purity.

S-MNTX, and its derivatives, are produced in the salt form. Derivativessuch as zwitterions of S-MNTX are included. S-MNTX, as shown in FIG. 1,may include a positively charged quaternary ammonium group and may bepaired with a counterion such as a monovalent or multivalent anion.These anions may include, for example, halides, sulfates, phosphates,nitrates and charged organic species such as sulfonates andcarboxylates. Preferred anions include halides such as bromide,chloride, iodide, fluoride, and combinations thereof. In someembodiments, bromide is most preferred. Specific anions may be chosenbased on factors such as, for example, reactivity, solubility,stability, activity, cost, availability and toxicity.

Counterions of the S-MNTX salt can be exchanged for alternativecounterion. When an alternative counterion is desired, an aqueoussolution of an S-MNTX salt can be passed over an anion exchange resincolumn to exchange some or all of the counterion of the S-MNTX salt fora preferred alternative counterion. Examples of anion exchange resinsinclude AG 1-X8 in a 100 to 200 mesh grade, available from Bio-Rad. Inanother embodiment, the S-MNTX cation can be retained on a cationexchange resin and can then be exchanged by removing the S-MNTX from theresin with a salt solution that includes a preferred anion, such asbromide or chloride, forming the desired S-MNTX salt in solution.

The S-MNTX of the present invention has numerous utilities. One aspectof the invention is S-MNTX as a chromatographic standard in identifyingand distinguishing S-MNTX from other components in a sample in achromatographic separation. Another aspect of the invention is the useof S-MNTX as a chromatographic standard in identifying anddistinguishing S-MNTX in a mixture containing S-MNTX and R-MNTX.Isolated S-MNTX is also useful in the development of protocols forpurifying and distinguishing S-MNTX from R-MNTX in reaction mixtures.Such protocols are described herein and also in co-pending applicationentitled “Synthesis of (R)-N-Methylnaltrexone”, attorney docket numberPO453.70119US00, filed on even date herewith.

The S-MNTX may be provided in a kit form with instruction for its use asa standard. The kit may further comprise an authentic R-MNTX as astandard. The S-MNTX for use as a standard preferably has a purity of99.8% or greater with no detectable R-MNTX.

One aspect of the invention is a method of resolving and identifyingS-MNTX and R-MNTX in a solution of MNTX. The S-MNTX also is useful inHPLC assay methods of quantifying an amount of S-MNTX in a compositionor mixture in which the method comprises applying a sample of thecomposition or mixture to a chromatography column, resolving thecomponents of the composition or mixture, and calculating the amount ofS-MNTX in the sample by comparing the percentage of a resolved componentin the sample with the percentage of a standard concentration of S-MNTX.The method is particularly useful in reverse phase HPLC chromatography.The S-MNTX of the present invention by virtue of its agonist activity onopioid receptors, is useful as a standard of agonist activity in invitro and in vivo opioid receptor assays such as those described herein.

The S-MNTX can be used to regulate a condition mediated by one or moreperipheral opioid receptors, prophylactically or therapeutically, toagonize peripheral opioid receptors, in particular peripheral mu opioidreceptors. The subjects being administered S-MNTX may receive treatmentacutely, chronically or on an as needed basis.

The subjects to which the S-MNTX is administered are vertebrates, inparticular mammals. In one embodiment the mammal is a human, nonhumanprimate, dog, cat, sheep, goat, horse, cow, pig and rodent. In apreferred embodiment, the mammal is a human.

Mu and other opioid receptors exist in the gastrointestinal tract. Ofthe major classes of opioid receptors in the GI tract, mu receptors areprincipally involved in modulation of GI activity. Kappa opioidreceptors may play a role (Manara L et al Ann. Rev. Phamacol. Toxicol,1985, 25:249-73). In general, the S-MNTX is used to prevent or treatconditions associated with the need for activation or modulation ofopioid receptors, in particular, peripheral opioid receptors. Ofinterest is the use of S-MNTX to prevent or treat conditions associatedwith the need for activation or modulation of opioid receptors in the GItract, in particular mu opioid receptors. Such conditions which may beprevented or treated include diarrhea and used to prevent or inhibitcertain forms of gastrointestinal dysfunction including certain forms ofinflammatory bowel syndrome, and eating and digestive disorders.

In one aspect, S-MNTX can be used to treat diarrhea. Gastrointestinalfunction is regulated, at least in part, by one or more opioid receptorsas well as endogenous opioids. Opioid antagonists are known to increasegastrointestinal motility and may thus be used effectively as atreatment for constipation. Opioid agonists on the other hand, inparticular peripheral opioid agonists such as loperamide are known todecrease gastrointestinal motility and can be useful in treatingdiarrhea in mammals. S-MNTX as discovered by Applicants as an opioidagonist, can be administered to a patient in need of treatment fordiarrhea. Diarrhea as used herein is defined as one or more of thefollowing: 1) stool loose in consistency; 2) passing of greater than 3stools per day; and/or 3) passing a stool volume of ≧200 g (150 ml) perday. S-MNTX is administered in an amount effective to prolong thetransit time of intestinal contents resulting in reduced fecal volume,increase fecal viscosity and bulk density and diminished loss of fluidand electrolytes.

The S-MNTX of the present invention by virtue of its opioid agonistactivity is useful in the prevention and treatment of diarrhea havingdiverse etiology including acute and chronic forms of diarrhea,including chronic functional (idiopathic) diarrhea.

Acute diarrhea or short-term diarrhea as used herein is diarrhea lastingless than 1 week in duration, typically 1 to 3 days. Chronic diarrhea,ongoing or prolonged diarrhea as used herein is diarrhea lasting 1. weekor longer duration. Chronic diarrhea may last for months or even yearsand may be continuous or intermittent. Various forms and causes ofdiarrhea which may benefit from treatment using S-MNTX include, but arenot limited to those described below.

Viral gastroenteritis or “stomach flu” caused by any virus including butnot limited to rotavirus, Norwalk virus, cytomegalovirus, herpes simplesvirus, Hepatitis virus, and Adenovirus, is amenable to treatment usingS-MNTX.

Food poisoning and traveler's diarrhea which occur from eating food ordrinking water contaminated with organisms such as bacteria andparasites are amenable to treatment using S-MNTX. Bacteria commonlycausing diarrhea include Escherichia coli, Salmonella, Shigella,Clostridia, Campylobacter, Yersinia, and Listeria. Parasites which causediarrhea include Giardia lamblia, Entamaeba histolytica, andCryptosporidium. Fungus which may cause diarrhea includes Candida.

Certain medical conditions can also lead to diarrhea includingmalabsorption syndromes such as lactose intolerance, celiac disease(sprue or gluten malabsorption), cystic fibrosis, intolerance to theprotein in cows milk or other specific foods like beans, or fruits.Allergies to specific foods is another condition which may causegastrointestinal irritation and/or allergic reaction leading todiarrhea. Typical food allergens include peanuts, corn and shellfish.Diarrhea caused by or associated with these medical conditions isamendable to treatment using S-MNTX of the present invention.

Other medical conditions that lead to diarrhea, in particular chronicdiarrhea include inflammatory bowel diseases which include Crohn'sdisease and ulcerative colitis, irritable bowel syndrome (IBS) andimmune deficiency may also benefit from S-MNTX to prevent or treat thediarrhea.

S-MNTX is useful in preventing and treating diarrhea caused bymedications and/or therapies such as antibiotics, laxatives containingmagnesium, chemotherapeutics for cancer treatment and high doseradiation therapy.

Diarrhea is also associated with Zollinger-Ellison syndrome, nervedisorders such as autonomic neuropathy or diabetic neuropathy, carcinoidsyndrome, vasoactive intestinal polypeptide-secreting tumor, andanatomical conditions of the gastrointestinal tract including shortbowel syndrome, gastrectomy, bowel resection with or without ileostomyor colostomy, and removal of the gall bladder. Such conditions areamenable to treatment using S-MNTX.

S-MNTX may be administered through any route, oral or parenteral,including intraperitoneal, intravenous, vaginal, rectal, intramuscular,subcutaneously, aerosol, nasal spray, transmucosal, transdermal,topical, colonic, and the like for the prevention and treatment ofdiarrhea.

S-MNTX is also useful in methods of reducing a volume of discharge froma ileostomy or cholostomy in a subject. The S-MNTX is provided in anamount effective to reduce the volume of discharge from the ostomy,compared to the volume of discharge from the ostomy in the absence ofS-MNTX. S-MNTX is also useful in controlling the rate of discharge froman ostomy, in particular in reducing the rate of discharge in a subjectin need of lower rate of discharge.

According to another aspect of the invention, a method is provided forinhibiting gastrointestinal motility in a subject. The method involvesadministering to a subject in need of such inhibition a pharmaceuticalcomposition containing S-MNTX in an amount effective to inhibitgastrointestinal motility in the subject. According to the invention,the S-MNTX may be administered in conjunction with another motilityinhibiting agent that is not S-MNTX. In one embodiment, the agent is anopioid or an opioid agonist. Opioids and opioid agonists are describedabove. In another embodiment, the agent is not an opioid or an opioidagonist. Examples of such nonopioid gastrointestinal motility inhibitingagents include, for example, cisapride, antacids, aluminum hydroxide,magnesium aluminum silicate, magnesium carbonate, magnesium hydroxide,calcium carbonate, polycarbophil, simethicone, hyoscyamine, atropine,furazolidone, difenoxin, octreotide, lansoprazole, kaolin, pectin,activated charcoal, sulphaguanidine, succinylsulphathiazole,phthalylsulphathiazole, bismuth-containing preparations such as bismuthaluminate, bismuth subcarbonate, bismuth subcitrate, bismuth citrate,tripotassium dicitrato bismuthate, bismuth tartrate, bismuthsubsalicylate, bismuth subnitrate and bismuth subgallate, opium tincture(paregoric), herbal medicines and plant-derived anti-diarrheal agents.Further such agents include benzodiazepine compounds, antispasmodic,selective serotonin reuptake inhibitors (SSRIs), cholecystokinin (CCK)receptor antagonists, natural killer (NK) receptor antagonists,Corticotropin Releasing Factor (CRF) receptor agonists, antacids, GIrelaxants, anti-gas compounds, pentosan polysulfate, anti-emeticdopamine D2 antagonists, gonadotrophin-releasing hormone analogues(leuprolide), corticotrophin-1 antagonists, neurokinin 2 receptorantagonists, cholecystokinin-1 antagonists, beta-blockers,anti-esophageal reflux agents, anti-inflammatory agents, 5HT₁agonists,5HT₃ antagonists, 5HT₄ antagonists, bile salt sequestering agents,bulk-forming agents, alpha₂-adrenergic agonists, antidepressants such astricyclic antidepressants. Additional such agents include antimuscarinicagents, ganglion blocking agents, hormones and hormone analogs, andmotilin receptor antagonists. Antimuscarinic agents include belladonnaalkaloids, quaternary ammonium antimuscarinic compounds and tertiaryamine antimuscarinic compounds. Examples of belladonna alkaloids includebelladonna leaf extracts, belladonna tincture, and belladonna extract.Examples of quaternary ammonium antimuscarinic agents includeAnisotropine or Anisotropine methylbromide (Valpin), Clidinium orClidinium bromide (Quarzan), Glycopyrrolate (Robinul), Hexocycliummethylsulfate (Tral), Homatropine, Ipratropium or Ipratropium bromide,Isopropamide or Isopropamide iodide (Darbid), Mepenzolate or Mepenzolatebromide (Cantil), Methantheline or Methantheline bromide (Banthine),Methscopolamine or Methscopolamine bromide (Pamine), Oxyphenonium, andPropantheline or Propantheline bromide. Examples of tertiary amineantimuscarinic agents include Atropine, Dicyclomine or Dicyclominehydrochloride (Bentyl and others), Flavoxate hydrochloride (Urispas),Oxybutynin or Oxybutynin chloride (Ditropan), Oxyphencyclimine orOxyphencyclimine hydrochloride (Daricon), Propiverine, Scopolamine,Tolterodine, and Tridihexethyl or Tridihexethyl chloride (Pathilon).Other antimuscarinic agents include Pirenzepine, Telenzepine, AF-DX116,Methoctranine, Himbacine, and Hexahydrosiladifenidol. Ganglion blockingagents include synthetic amines such as Hexamethonium, Mecamylamine,Tetraethylammonium, and Acetylcholine. Examples of hormones or hormoneanalogs that are anti-gastrointestinal motility agents include:somatostatin and somatostatin receptor agonists. Examples ofsomatostatin analogs include octreotide (e.g., Sandostatin®) andvapreotide. Motilin to antagonists include (Phe3, Leu-13) porcinemotilin, 214^(th) American Chemical Society (ACS) Meeting (Part V);Highlights from Medicinal Chemistry Poster Session, Wednesday 10September, Las Vegas, Nevada, (1997), Iddb Meeting Report Sep. 7-11(1997); and ANQ-1 1 125, Peeters T. L., et al., Biochem. Biophys. Res.Commun., Vol. 198(2), pp. 411-416 (1994).

In another aspect, S-MNTX may be used to treat eating and digestivedisorders. Eating disorders and digestive disorders amenable totreatment using S-MNTX according to the invention comprise, but are notlimited to, the regulation of pathological imbalanced appetite, loss ofappetite or diminished appetite, induced for example by pregnancy,cancer, infectious diseases such as influenza, HCV or HIV, as a resultof catabolism, cachexy, anorexia, especially anorexia nervosa,dysorexia, dysponderosis, adiposity, bulimia, obesity, gastroparesis,especially neurogenic gastroparesis, diabetic gastroparesis, myogenicgastroparesis or gastroparesis induced by drugs, gastroatonia,gastroparalysis or enteroparesis, and stenosis of the gastrointestinaltract, especially stenosis of the pylorus.

Pain has been defined in a variety of ways. For example, pain can bedefined as the perception by a subject of noxious stimuli that producesa withdrawal reaction by the subject Analgesia, is the reduction of painperception. Agents that selectively block an animal's response to astrong stimulus without obtunding general behavior or motor function arereferred to as analgesics. Opiates and opioid agonists affect pain viainteraction with specific opioid receptors. Given the discovery thatS-MNTX has opiate agonist activity on gastrointestinal transit in rats,there is a rationale for using S-MNTX in treatment of pain.

In general, administration of S-MNTX and derivatives thereof accordingto the invention can be used to facilitate management of pain that isassociated with any of a wide variety of disorders, conditions, ordiseases. “Pain” as used herein, unless specifically noted otherwise, ismeant to encompass pain of any duration and frequency, including, butnot limited to, acute pain, chronic pain, intermittent pain, and thelike. Causes of pain may be identifiable or unidentifiable. Whereidentifiable, the origin of pain may be, for example, of malignant,non-malignant, infectious, non-infectious, or autoimmune origin. Oneembodiment is the management of pain associated with diseases,disorders, or conditions that require short-term therapy, e.g., dentalprocedures, bone fractures, outpatient surgeries, for which therapyinvolves treatment over a period of hours up to 3 days. Of particularinterest is the management of pain associated with disorders, diseases,or conditions that require long-term therapy, e.g., chronic and/orpersistent diseases or conditions for which therapy involves treatmentover a period of several days (e.g., about 3 days to 10 days), toseveral weeks (e.g., about 2 weeks or 4 weeks to 6 weeks), to severalmonths or years, up to and including the remaining lifetime of thesubject; Subjects who are not presently suffering from a disease orcondition, but who are susceptible to such may also benefit fromprophylactic pain management using the compositions and methods of theinvention, e.g., prior to traumatic surgery. Pain amenable to therapyaccording to the invention may involve prolonged episodes of painalternating with pain-free intervals, or substantially unremitting painthat varies in severity.

In general, pain can be nociceptive, somatogenic, neurogenic, orpsychogenic. Somatogenic pain can be muscular or skeletal (i.e.,osteoarthritis, lumbosacral back pain, posttraumatic, myofascial),visceral (i.e., pancreatitis, ulcer, irritable bowel), ischemic (i.e.,arteriosclerosis obliterans), or related to the progression of cancer(e.g., malignant or non-malignant). Neurogenic pain can be due toposttraumatic and postoperative neuralgia, can be related toneuropathies (i.e., diabetes, toxicity, etc.), and can be related tonerve entrapment, facial neuralgia, perineal neuralgia, postamputation,thalamic, causalgia, and reflex sympathetic dystrophy.

Specific examples of conditions, diseases, disorders, and origins ofpain amenable to management according to the present invention include,but are not necessarily limited to, cancer pain (e.g., metastasis ornon-metastatic cancer), inflammatory disease pain, neuropathic pain,postoperative pain, iatrogenic pain (e.g., pain following invasiveprocedures or high dose radiation therapy, e.g., involving scar tissueformation resulting in a debilitating compromise of freedom of motionand substantial pain), complex regional pain syndromes, failed-back pain(e.g., acute or chronic back pain), soft tissue pain, joints and bonepain, central pain, injury (e.g., debilitating injuries, e.g.,paraplegia, quadriplegia, etc., as well as non-debilitating injury(e.g., to back, neck, spine, joints, legs, arms, hands, feet, etc.)),arthritic pain (e.g., rheumatoid arthritis, osteoarthritis, arthriticsymptoms of unknown etiology, etc.), hereditary disease (e.g., sicklecell anemia), infectious disease and resulting syndromes (e.g., Lymedisease, AIDS, etc.), headaches (e.g., migraines), causalgia,hyperesthesia, sympathetic dystrophy, phantom limb syndrome,denervation, and the like. Pain can be associated with any portion(s) ofthe body, e.g., the musculoskeletal system, visceral organs, skin,nervous system, etc.

The methods of the invention can be used to manage pain in patients whoare opioid naïve or who are no longer opioid naïve. Exemplary opioidnave patients are those who have not received long-term opioid therapyfor pain management. Exemplary non-opioid naïve patients are those whohave received short-term or long-term opioid therapy and have developedtolerance, dependence, or other undesirable side effect. For example,patients who have intractable adverse side effects with oral,intravenous, or intrathecal morphine, transdermal fentanyl patches, orconventionally administered subcutaneous infusions of fentanyl, morphineor other opioid can achieve good analgesia and maintain favorableside-effects profiles with deliver of S-MNTX and derivatives thereof.

The term “pain management or treatment” is used here to generallydescribe regression, suppression, or mitigation of pain so as to makethe subject more comfortable as determined by subjective criteria,objective criteria, or both. In general, pain is assessed subjectivelyby patient report, with the health professional taking intoconsideration the patient's age, cultural background, environment, andother psychological background factors known to alter a person'ssubjective reaction to pain.

As mentioned above, S-MNTX can be administered together with atherapeutic agent that is not S-MNTX, including but not limited,therapeutic agents that are pain relieving agents. In one embodiment,the pain relieving agent is an opioid or opioid agonist. In anotherembodiment, the pain relieving agent is a nonopioid pain relieving agentsuch as a corticosteroid or a nonsteroidal anti-inflammatory drug(NSAID). Pain relieving agents include: Alfentanil Hydrochloride;Aminobenzoate Potassium; Aminobenzoate Sodium; Anidoxime; Anileridine;Anileridine Hydrochloride; Anilopam Hydrochloride; Anirolac; Antipyrine;Aspirin; Benoxaprofen; Benzydamine Hydrochloride; BicifadineHydrochloride; Brifentanil Hydrochloride; Bromadoline Maleate; BromfenacSodium; Buprenorphine Hydrochloride; Butacetin; Butixirate; Butorphanol;Butorphanol Tartrate; Carbamazepine; Carbaspirin Calcium; CarbipheneHydrochloride; Carfentanil Citrate; Ciprefadol Succinate; Ciramadol;Ciramadol Hydrochloride; Clonixeril; Clonixin; Codeine; CodeinePhosphate; Codeine Sulfate; Conorphone Hydrochloride; Cyclazocine;Dexoxadrol Hydrochloride; Dexpemedolac; Dezocine; Diflunisal;Dihydrocodeine Bitartrate; Dimefadane; Dipyrone; DoxpicomineHydrochloride; Drinidene; Enadoline Hydrochloride; Epirizole; ErgotamineTartrate; Ethoxazene Hydrochloride; Etofenamate; Eugenol; Fenoprofen;Fenoprofen Calcium; Fentanyl Citrate; Floctafenine; Flufenisal;Flunixin; Flunixin Meglumine; Flupirtine Maleate; Fluproquazone;Fluradoline Hydrochloride; Flurbiprofen; Hydromorphone Hydrochloride;Ibufenac; Indoprofen; Ketazocine; Ketorfanol; Ketorolac Tromethamine;Letimide Hydrochloride; Levomethadyl Acetate; Levomethadyl AcetateHydrochloride; Levonantradol Hydrochloride; Levorphanol Tartrate;Lofemizole Hydrochloride; Lofentanil Oxalate; Lorcinadol; Lornoxicam;Magnesium Salicylate; Mefenamic Acid; Menabitan Hydrochloride;Meperidine Hydrochloride; Meptazinol Hydrochloride; MethadoneHydrochloride; Methadyl Acetate; Methopholine; Methotrimeprazine;Metkephamid Acetate; Mimbane Hydrochloride; Mirfentanil Hydrochloride;Molinazone; Morphine Sulfate; Moxazocine; Nabitan Hydrochloride;Nalbuphine Hydrochloride; Nalmexone Hydrochloride; Namoxyrate; NantradolHydrochloride; Naproxen; Naproxen Sodium; Naproxol; NefopamHydrochloride; Nexeridine Hydrochloride; Noracymethadol Hydrochloride;Ocfentainl Hydrochloride; Octazamide; Olvanil; Oxetorone Fumarate;Oxycodone; Oxycodone Hydrochloride; Oxycodone Terephthalate; OxymorphoneHydrochloride; Pemedolac; Pentamorphone; Pentazocine; PentazocineHydrochloride; Pentazocine Lactate; Phenazopyridine Hydrochloride;Phenyramidol Hydrochloride; Picenadol Hydrochloride; Pinadoline;Pirfenidone; Piroxicam Olamine; Pravadoline Maleate; ProdilidineHydrochloride; Profadol Hydrochloride; Propiram Fumarate; PropoxypheneHydrochloride; Propoxyphene Napsylate; Proxazole; Proxazole Citrate;Proxorphan Tartrate; Pyrroliphene Hydrochloride; RemifentanilHydrochloride; Salcolex; Salethamide Maleate; Salicylamide; SalicylateMeglumine; Salsalate; Sodium Salicylate; Spiradoline Mesylate;Sufentanil; Sufentanil Citrate; Talmetacin; Talniflumate; Talosalate;Tazadolene Succinate; Tebufelone; Tetrydamine; Tifurac Sodium; TilidineHydrochloride; Tiopinac; Tonazocine Mesylate; Tramadol Hydrochloride;Trefentanil Hydrochloride; Trolamine; Veradoline Hydrochloride;Verilopam Hydrochloride; Volazocine; Xorphanol Mesylate; XylazineHydrochloride; Zenazocine Mesylate; Zomepirac Sodium; Zucapsaicin, andcombinations thereof.

Hyperalgesia is an increased senisitivy to pain or enhanced intensity ofpain sensation. Hyperalgesia can result when a subject is hypersensitiveto a stimulus, resulting in an exaggerated pain response to a givenstimulus Hyperalgesia is often the result of a local inflammatory stateand may follow trauma or injury to body tissue . Inflammation mayfollow, or be associated with, local infection, blisters, boils, skininjury such as cuts, scrapes, burns, sunburns, abrasions, surgicalincisions, inflammatory skin conditions such as poison ivy, allergicrashes, insect bites and stings, and joint inflammation. S-MNTX can beused to prevent and treat peripheral hyperalgesia and to reduce painand/or symptoms resulting from inflammation. As used herein,hyperalgesia includes pruritis, or itching, and S-MNTX may be used as ananti-pruritic treatment.

The compositions and methods herein are intended for the preventions andtreatment of hyperalgesia association with numerous inflammatoryconditions and injuries. The compositions and methods provided hereinmay be used to treat a variety of hyperalgesic conditions associatedwith burns, including, but not limited to, thermal, radiation, chemical,sun and wind bums, abrasions, including, for example, corneal abrasions,bruises, contusions, frostbite, rashes, including, for example, allergicheat and contact dermatitis, such as, for example, poison ivy and diaperrashes, acne, insect bites/stings, skin ulcers, including, but notlimited to, diabetic and decubitus ulcers, mucositis, inflammation, forexample, periodontal inflammation, orthodontic inflammation,inflammation/irritation arising from use of a cosmetic or skin careproduct, inflammatory conjunctivitis, hemorrhoids and venerealinflammations, gingivitis, bronchitis, laryngitis, sore throat, singles,fungal irritation, for example, athlete's foot and jock itch, feverblisters, boils, plantar's warts or vaginal lesions, including, forexample, mycotic and sexually transmitted vaginal lesions.

Hyperalgesic conditions associated with skin surfaces include bums,including but not limited to, thermal, radiation, chemical, sun and windburns, abrasions such as, for example, corneal abrasions, bruises,contusions, frostbite, rashes including allergic, heat contactdermatitis (for example, poison ivy) and diaper rashes), acne insectbites/stings and skin ulcers (including diabetic and decubitus ulcers).Hyperalgesic conditions of the mouth, larynx and bronchium includemucositis, post-tooth extraction, periodontal inflammation, gingivitis,orthodontic inflammation, bronchitis, laryngitis and sore throat.Hyperalgesic conditions of the eyes include corneal *abrasions,post-radial keratectomy and inflammatory conjunctivitis. Hyperalgesicconditions of the rectum/anus include hemorrhoids and venerealinflammations. Hyperalgesic conditions associated with infectious agentsinclude shingles, fungal irritations (including athlete's foot and jockitch), fever blisters, boils, plantar's warts and vaginal lesions(including lesions associated with mycosis and sexually transmitteddiseases). Hyperalgesic conditions may also be associated with recoveryfollowing surgery, such as recovery following lumpectomy, episiotomy,laparoscopy, arthroscopy, radial keratectomy and tooth extraction.

As a preventative or treatment for peripheral hyperalgesia, S-MNTX canbe administered using any pathway that provides for delivery of thecompound to an afflicted area. Administration may be oral or parenteral.Methods of administration also include topical and local administration.S-MNTX can be applied to any body surface including skin, joints, eyes,lips and mucosal membranes.

S-MNTX may be delivered in combination with other compounds, such asthose disclosed herein, that provide anti-hyperalgesic effects,including, but not limited to, pain medications, itching medications,anti-inflammatory agents, and the like. S-MNTX also may be administeredwith other compounds used to treat the conditions causing theinflammation, such as antivirals, antibacterials, antifungals, andanti-infectives. These other compounds may act and be administeredlocally or systemically and may be part of the same composition or maybe administered separately. Such compounds are described in greaterdetail below.

Inflammation is often associated with an increase in Tumor NecrosisFactor (TNF) production and it is believed that a decrease in TNFproduction will result in a reduction in inflammation. Peripherallyacting opioid agonists have been shown to decrease TNF production (U.S.Pat. No. 6,190,691). The peripherally selective k-opioid, asimadoline,has been shown to be a potent anti-arthritic agent in anadjuvant-induced arthritis animal model (Binder, W. and Walker, J. S.Br. J. Pharma 124:647-654). Thus the peripheral opioid agonist activityof S-MNTX and derivatives thereof provide for prevention and treatmentof inflammatory conditions. While not being bound by theory, theanti-inflammatory effect of S-MNTX and derivatives thereof may bethrough inhibition of TNF production, directly or indirectly. The S-MNTXor derivatives thereof may be administered systemically or locally.S-MNTX may be administered in combination with another TNF inhibitorsuch as loperamide and diphenoxylate or with other anti-inflammatoryagents described herein.

Another aspect of the present invention is prevention and/or treatmentof a systemic inflammatory condition, preferably inflammatory boweldisease, rheumatoid arthritis, cachexia, asthma, Crohn's disease,endotoxin shock, adult respiratory distress syndrome,ischemic/reperfusion damage, graft-versus-host reactions, boneresorption, transplantation or lupus using S-MNTX or derivativesthereof.

In still another group of embodiments, the inflammatory conditionamenable to treatment using S-MNTX or derivatives thereof is associatedwith multiple sclerosis, diabetes or wasting associated with acquiredimmunodeficiency syndrome (AIDS) or cancer.

In one group of embodiments, a skin inflammatory condition, preferablypsoriasis, atopic dermatitis, UV-induced inflammation, contactdermatitis or inflammation induced by other drugs, including, but notlimited to RETIN-A (all-trans-retinoic acid) is amenable to treatmentusing S-MNTX or derivative thereof.

Another aspect of the invention is a method of treating a non-allergicinflammatory skin condition comprising the administration of S-MNTX inan amount effective to treat the inflammatory condition. Non-allergicinflammatory skin conditions are associated with irritant contactdermatitis, psoriasis, eczema, pruritus, seborrheic dermatitis, nummulardermatitis, lichen planus, acne vulgaris, comedones, polymorphs,nodulokystic acne, conglobata, senile acne, secondary acne, medicinalacne, a keratinization disorder, and blistery dermatoses.

Certain patients particularly amenable to treatment are patients havingthe symptoms of any one of the foregoing conditions. The patients mayhave failed to obtain relief or ceased to obtain relief or a consistentdegree of relief of their symptoms using other therapies. Such patientsare said to be refractory to the conventional treatments. The conditionmay be induced or a consequence of one or more diverse conditionsincluding, but not limited to, a disease condition, a physicalcondition, a drug-induced condition, a physiological imbalance, stress,anxiety, and the like. The conditions may be an acute condition orchronic condition.

Subjects can be treated with a combination of the S-MNTX and atherapeutic agent other than the S-MNTX. In these circumstances theS-MNTX and the other therapeutic agent(s) are administered close enoughin time such that the subject experiences the effects of the variousagents as desired, which typically is at the same time. In someembodiments the S-MNTX will be delivered first in time, in someembodiments second in time, and still in some embodiments at the sametime. As discussed in greater detail below, the invention contemplatespharmaceutical preparations where the S-MNTX is administered in aformulation including another pharmaceutical agent. These formulationsmay be such as those described in U.S. patent application Ser. No.10/821,809, which is hereby incorporated by reference in its entiretyherein. Included are solid, semisolid, liquid, controlled release andother such formulations.

One important class of therapeutic agent which can be part of theprevention and treatment protocol together with the S-MNTX are opioids.It has been surprisingly found by Applicants that S-MNTX used incombination with the opioid, morphine results in an enhanced andapparently synergistic inhibition of gastrointestinal transit. Thus, thepresent invention provides pharmaceutical compositions comprising S-MNTXin combination with one or more opioids. This will permit alteration ofdoses not previously obtainable. For example, where a lower dose ofopioid is desirable in treating certain peripherally mediated conditionsthis now is possible by combination with S-MNTX treatment.

The opioid can be any pharmaceutically acceptable opioid. Common opioidsare those selected from the group consisting of alfentanil, anileridine,asimadoline, bremazocine, burprenorphine, butorphanol, codeine,dezocine, diacetylmorphine (heroin), dihydrocodeine, diphenoxylate,fedotozine, fentanyl, funaltrexamine, hydrocodone, hydromorphone,levallorphan, levomethadyl acetate, levorphanol, loperamide, meperidine(pethidine), methadone, morphine, morphine-6-glucoronide, nalbuphine,nalorphine, opium, oxycodone, oxymorphone, pentazocine, propiram,propoxyphene, remifentanyl, sufentanil, tilidine, trimebutine, andtramadol.

Depending on the desired effect to be achieved the opioid may beadministered parenterally or other systemic route to affect both thecentral nervous system (CNS) and peripheral opioid receptors. Thedesired effect of the opioid in combination with S-MNTX may beprevention or treatment of diarrhea, prevention or treatment of painfrom any cause or etiology including prevention or treatment ofperipheral hyperalgesia. When the indication is prevention or treatmentof peripheral hyperalgesia, it is desirable to provide an opioid whichdoes not have concomitant CNS effects or alternatively to administer theopioid topically or locally such that the opioid does not substantiallycross the blood brain barrier but provide an effect on peripheral opioidreceptors.

Opioids particularly useful for prevention or treatment of diarrhea orprevention or treatment of peripheral hyperalgesia in combination withS-MNTX include but are not to limited to:

(i) loperamide[4-(p-chlorophenyl)-4-hydroxy-N-N-dimethyl-α,α-diphenyl-1-piperidinebutyramidehydrochloride]], loperamide analogs and related compounds as definedherein [see, U.S. Pat. Nos. 3,884,916 and 3,714,159; see, also U.S. Pat.Nos. 4,194,045, 4,116,963, 4,072,686, 4,069,223, 4,066,654.], N-oxidesof loperamide and analogs, metabolites and prodrugs thereof and relatedcompounds as defined herein [see, also, U.S. Pat. No. 4,824,853], andrelated compounds, such as (a), (b) and (c) as follows:

-   -   (a) 4-(aroylamino)pyridine-butanamide derivatives and N-oxides        thereof as defined herein [see, also U.S. Pat. No. 4,990,521];    -   (b) 5-(1,1-diphenyl-3-(5- or        6-hydroxy-2-a7abicyclo-(2.2.2)oct-2-yl)propyl)-2-alkyl-1,3,4-oxadiazoles,        5-(1,1-diphenyl-4-(cyclic        amino)but-2-trans-en-1-yl)-2-alkyl-1,3,4-oxadiazoles,        2-[5-(cyclic        amino)-ethyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5-yl]-5-alkyl-1,3,4-oxadiazoles]        and related compounds [see, U.S. Pat. Nos. 4,013,668, 3,996,214        and 4,012,393];    -   (c) 2-substituted-1-azabicyclo[2,2,2]octanes [see, U.S. Pat. No.        4,125,531];

(ii) 3-hydroxy-7-oxomorphinans and 3-hydroxy-7-oxoisomorphinans [see,e.g., U.S. Pat. No. 4,277,605]

(iii) amidinoureas as provided herein [see, also U.S. Pat. Nos.4,326,075, 4,326,074, 4203,920, 4,060,635, 4,115,564, 4,025,652] and2-[(aminophenyl and amidophenyl)amino]-1-azacycloalkanes [see, U.S. Pat.No. 4,533,739];

(iv) metkephamid [H-L-Tyr-D-Ala-Bly-L-Phe-N(Me)Met-NH₂; see, e.g., U.S.Pat. No. 4,430,327; Burkhart et al. (1982) Peptides 3-869-871;Frederickson et al. (1991) Science 211:603-605] and other syntheticopioid peptides, such as H-Tyr-D-Nva-Phe-Orn-NH₂,H-Tyr-D-Nle-Phe-Orn-NH₂, H-Tyr-D-Arg-Phe-A₂bu-NH₂,H-Tyr-D-Arg-Phe-Lys-NH₂, and H-Lys-Tyr-D-Arg-Phe-Lys-NH₂ [see, U.S. Pat.No. 5,312,899; see, also Gesellchen et al. (1981) Pept.: Synth.,Struct., Fund., Proc. Am. Pept. Symp., 7^(th); Rich et al., (Eds),Pierce Chem. Co., Rochford, Ill., pp. 621-62] that do not cross theblood brain barrier;

(v) propanamines as defined in U.S. Pat. No. 5,236,947 and the like.

S-MNTX may also be used to treat diarrhea in combination with otheranti-diarrheal compounds and compositions. For example, S-MNTX may beadministered to a subject in combination with a known anti-diarrhealagent. Two or more compounds may be administered in a cocktail or thecompounds may be administered separately using the same or differentadministration routes. Known anti-diarrheal agents include, for example,loperamide, loperamide analogs, N-oxides of loperamide and analogs,metabolites and prodrugs thereof, diphenoxylate, cisapride, antacids,aluminum hydroxide, magnesium aluminum silicate, magnesium carbonate,magnesium hydroxide, calcium carbonate, polycarbophil, simethicone,hyoscyamine, atropine, furazolidone, difenoxin, octreotide,lansoprazole, kaolin, pectin, activated charcoal, sulphaguanidine,succinylsulphathiazole, phthalylsulphathiazole, bismuth aluminate,bismuth subcarbonate, bismuth subcitrate, bismuth citrate, tripotassiumdicitrato bismuthate, bismuth tartrate, bismuth subsalicylate, bismuthsubnitrate and bismuth subgallate, opium tincture (paregoric), herbalmedicines and plant-derived anti-diarrheal agents.

Other therapeutic agents which can be part of treatment protocolstogether with S-MNTX are irritable bowel syndrome (IBS) agents,antibiotics, antivirals, anti-fungals, anti-infectives,anti-inflammatory agents including anti-histamines, vasoconstrictors,anti-diarrheals, and the like.

IBS therapeutic agents which may be used in combination with S-MNTXinclude, but are not limited to, benzodiazepine compounds,antispasmodic, selective serotonin reuptake inhibitors (SSRIs),cholecystokinin (CCK) receptor antagonists, motilin receptor agonists orantagonists, natural killer (NK) receptor antagonists, CorticotropinReleasing Factor (CRF) receptor agonists or antagonists, somatostatinreceptor agonists, antacids, GI relaxants, anti-gas compounds,bismuth-containing preparations, pentosan polysulfate, anti-emeticdopamine D2 antagonists, prostaglandin E analogs,gonadotrophin-releasing hormone analogues (leuprolide), corticotrophin-1antagonists, neurokinin 2 receptor antagonists, cholecystokinin-1antagonists, beta-blockers, anti-esophageal reflux agents,anti-muscarinics, antidiarrheals, anti-inflammatory agents,anti-motility agents, 5HT₁ agonists, 5HT₃ antagonists, 5HT₄ antagonists,5HT₄ agonists, bile salt sequestering agents, bulk-forming agents,alpha₂-adrenergic agonists, mineral oils, antidepressants, herbalmedicines. Specific examples of IBS therapeutic agents include, but arenot limited to, the following:

Benzodiazepine compounds and analogs which act to suppress seizuresthrough an interaction with gamma-aminobutyric acid (GABA) receptors ofthe A-type (GABA_(A)), for example, DIASTAT® and VALIUM®; LIBRIUM®; andZANAX®.

SSRIs, for example, fluvoxamine; fluoxetine; paroxetine; sertraline;citalopram; venlafaxine; cericlamine; duloxetine; milnacipran;nefazodone; and cyanodothiepin (See The Year Drugs News, 1995 Edition,pp. 47-48 by Prous J. R.) and WO 97/29739.

CCK receptor antagonists, for example, devazepide; lorglumide;dexioxiglumide; loxiglumide, D'Amato, M. et al., Br. J. Pharmacol. Vol.102(2), pp. 391-395 (1991); Cl 988; L364,718; L3637260; L740,093 andLY288,513; CCK receptor antagonists disclosed in U. S. Pat. No.5,220,017, Bruley-Des-Varannes, S, et al. Gastroenterol. Clin. Biol.Vol.15.(10)9 pp. 744-757 (1991), and Worker C: EUPHAR'99—Second EuropeanCongress of Pharmacology (Part IV) Budapest, Hungary Iddb Meeting Report1999 July 3-7.

Motilin receptor agonists or antagonists which include e.g. motilinagonist ABT-269, (erythromycin, 8,9-didehydro-N-dimethyldeoxo-4″,6,12-trideoxy-6,9-epoxy-N-ethyl),de(Nmethyl-N-ethyl-8,9-anhydroerythromycin A) andde(N-methyl)-N-isoprop-8,9anhydroerythromycin A), Sunazika T. et al.,Chem. Pharm. Bull., Vol. 37(10), pp. 2687-2700 (1989); A-173508 (AbbotLaboratories); motilin antagonists (Phe3, Leu-13) porcine motilin,214^(th) American Chemical Society (ACS) Meeting (Part V); Highlightsfrom Medicinal Chemistry Poster Session, Wednesday 10 September, LasVegas, Nev., (1997), Iddb Meeting Report Sep. 7-11 (1997); and ANQ-1 1125, Peeters T. L., et al., Biochern. Biophys. Res. Commun., Vol.198(2), pp. 411-416 (1994).

NK receptor antagonists which include e.g. FK 888(Fujisawa); GR 205171(Glaxo Wellcome); LY 303870 (Lilly); MK 869 (Merck); GR82334 (GlaxoWellcome); L758298 (Merck); L 733060 (Merck); L 741671 (Merck); L 742694(Merck); PD 154075 (Parke-Davis); S1 8523 (Servier); S 19752 (Servier);OT 7100 (Otsuka); WIN 51708 (Sterling Winthrop); NKP-608A; TKA457;DNK333; CP-96345; CP-99994; CP122721; L-733060; L-741671; L742694;L-758298; L-754030; GR-203040; GR-205171; RP-67580; RPR-100893(dapitant); RPR-107880; RPR-111905; FK-888; SDZ-NKT-343; MEN-10930;MEN-11149; S-18523; S-19752; PD-154075 (CAM-4261); SR-140333; LY-303870(lanepitant); EP-00652218; EP00585913; L-737488; CGP-49823; WIN-51708;SR-48968 (saredutant); SR-144190; YM383336; ZD-7944; MEN-10627;GR-159897; RPR-106145; PD-147714 (CAM-2291); ZM253270; FK-224; MDL-105212A; MDL-105172A; L-743986; L-743986 analogs; S-16474; SR-1 42801(osanetant); PD-161182; SB-223412; and SB-222200.

CRF receptor agonists or antagonists, e.g. as disclosed in WO 99/40089,AXC 2219, Antalarmin, NGD 1, CRA 0165, CRA 1000, CRA 1001.

Somatostatin receptor agonists, e.g. octreotide, vapreotide, lanreotide.

Anti-inflammatory compounds, particularly those of the immuno-modulatorytype, for example, NSAIDS; Tumor Necrosis Factor (TNF, TNFa) inhibitors;basiliximab (e.g. SIMULECT®); daclizumab (e.g. ZENAPAX®); infliximab(e.g. REMICADE®); etanercept (e.g. ENBREL®)mycophenolate mofetil (e.g.CELLCEPT®); azathioprine (e.g. IMURAN®); tacrolimus (e.g. PROGRAF®);steroids; methotrexate and GI anti-inflammatory agents, for example,sulfasalazine (e.g. AZULFIDINE®); olsalazine (e.g. DIPENTUM®); andmesalamine (e.g. ASACOL®, PENTASA®, ROWASA®).

Antacids, such as aluminum and magnesium antacids; and calciumhydroxides such as MAALOX®.

Anti-gas compounds, for example, simethicone marketed under the tradenames MYLANTA® and MYLICON®; and enzyme preps including PHAZYME® andBEANO®.

Bismuth-containing preparations, for example, bismuth subsalicylate alsoknown as PEPTO-BISMOL®.

Pentosan polysulfate, a heparin-like macromolecular carbohydratederivative which chemically and structurally resemblesglycosaminoglycans, marketed under the trade name ELMIRON®.

Anti-emetic dopamine D2 antagonists which include e.g. domperidone.

Prostaglandin E analogs, gonadotrophin-releasing hormone analogues(leuprolide), corticotrophin-1 antagonists, neurokinin 2 receptorantagonists, cholecystokinin-1 antagonists, beta-blockers.

Anti-esophageal reflux agents include but are not limited to PRILOSEC®.

Antispasmodics and anti-muscarinics include, but are not limited to,dicyclomine, oxybutyin (e.g., oxybutynin chloride), tolterodine (e.g.,tolterodine tartarate), alverine anisotropine, atropine (e.g., atropinesulfate), belladonna, homatropine, homatropine methobromide, hyoscyamine(e.g., hyoscyamine sulfate), methscopolamine, scopolamine (e.g.,scopolamine hydrochloride), clidinium, cimetropium, hexocyclium,pinaverium, otilonium, glycopyrrolate, and mebeverine.

Antidiarrheals include, but are not limited to, ipratropium,isopropamide, mepenzolate, propantheline, oxyphencylcimine, pirenzepine,diphenoxylate (e.g., diphenoxylate hydrochloride), atropine sulfate,alosetron hydrochloride, difenoxin hydrochloride, bismuth subsalicylate,lactobacillus acidophilus, trimebutine, asimadoline, and octreotideacetate.

Anti-inflammatory agents also include, but are not limited to,mesalamine, sulfasalazine, balsalazide disodium, hydrocortisone, andolsalazine sodium.

5HT₁ agonists include, but are not limited to, buspirone.

5HT₃ antagonists include, but are not limited to, ondansetron,cilansetron, and alosetron.

5HT₄ antagonists include, but are not limited to, piposcrod.

5HT₄ agonists include, but are not limited to, tegaserod (e.g.,tegaserod maleate), and povcalopride.

Antidepressants include, but are not limited to, desiprimine,amitryptiline, imiprimine, fluoxetine, and paroxetine.

Other IBS therapeutic agents include dexloxiglumide, TAK-637, talnetant,SB 223412, AU 244, neurotrophin-3, GT 160-246, immunoglobulin (IgG),ramoplanin, risaxmin, rimethicone, darifenacine, zamifenacin,loxiglumide, misoprostil, leuprolide, domperidone, somatostatinanalogues, phenytoin, NBI-34041, saredutant, and dexloxiglumide.

Antibiotics include, but are not limited to, tetracycline antibiotics,such as chlortetracycline, oxytetracycline, tetracycline,demethylchlortetracycline, metacycline, doxycycline, minocycline androlitetracycline; such as kanamycin, amikacin, gentamicin C_(1a), C₂,C_(2b) or C₁, sisomicin, netilmicin, spectinomycin, streptomycin,tobramycin, neomycin B, dibekacin and kanendomycin; macrolides, such asmaridomycin and erythromycin; lincomycins, such as clindamycine andlincomycin; penicillanic acid (6-APA)- and and cephalosporanic acid(7-ACA)-derivatives having (6β- or 7β-acylamino groups, respectively,which are present in fermentatively, semi-synthetically or totallysynthetically obtainable 6β-acylaminopenicillanic acid or7β-acylaminocephalosporanic acid derivatives and/or7β-acylaminocephalosporanic acid derivatives that are modified in the3-position, such as penicillanic acid derivatives that have become knownunder the names penicillin G or V, such as phenethicillin, propicillin,nafcillin, oxycillin, cloxacillin, dicloxacillin, flucloxacillin,cyclacillin, epicillin, mecillinam, methicillin, azlocillin,sulbenicillin, ticarcillin, mezlocillin, piperacillin, carindacillin,azidocillin or ciclacillin, and cephalosporin derivatives that havebecome known under the names cefaclor, cefuroxime, cefazlur,cephacetrile, cefazolin, cephalexin, cefadroxil, cephaloglycin,cefoxitin, cephaloridine, cefsulodin, cefotiam, ceftazidine, cefonicid,cefotaxime, cefmenoxime, ceftizoxime, cephalothin, cephradine,cefamandol, cephanone, cephapirin, cefroxadin, cefatrizine, cefazedone,ceftrixon and ceforanid; and other β-lactam antibiotics of the clavam,penem and carbapenen type, such as moxalactam, clavulanic acid,nocardicine A, sulbactam, aztreonam and thienamycin; and otherantibiotics including bicozamycin, novobiocin, chloramphenicol orthiamphenicol, rifampicin, fosfomycin, colistin, and vancomycin.

Antiviral agents include, but are not limited to, nucleoside analogs,nonnucleoside reverse transcriptase inhibitors, nucleoside reversetranscriptase inhibitors, protease inhibitors, integrase inhibitors,including the following: acemannan; acyclovir; acyclovir sodium;adefovir; alovudine; alvircept sudotox; amantadine hydrochloride;aranotin; arildone; atevirdine mesylate; avridine; cidofovir;cipamfylline; cytarabine hydrochloride; delavirdine mesylate;desciclovir; didanosine; disoxaril; edoxudine; enviradene; enviroxime;famciclovir; famotine hydrochloride; fiacitabine; fialuridine;fosarilate; foscarnet sodium; fosfonet sodium; ganciclovir; ganciclovirsodium; idoxuridine; indinavir; kethoxal; lamivudine; lobucavir;lopinovir; memotine hydrochloride; methisazone; nelfinavir; nevirapine;penciclovir; pirodavir; ribavirin; rimantadine hydrochloride; ritonavir;saquinavir mesylate; somantadine hydrochloride; sorivudine; statolon;stavudine; tenofovir; tilorone hydrochloride; trifluridine; valacyclovirhydrochloride; vidarabine; vidarabine phosphate; vidarabine sodiumphosphate; viroxime; zalcitabine; zerit; zidovudine (AZT); andzinviroxime.

Anti-infective agents include, but are not limited to, difloxacinhydrochloride; lauryl isoquinolinium bromide; moxalactam disodium;ornidazole; pentisomicin; sarafloxacin hydrochloride; proteaseinhibitors of HIV and other retroviruses; integrase Inhibitors of HIVand other retroviruses; cefaclor (ceclor); acyclovir (zovirax);norfloxacin (noroxin); cefoxitin (mefoxin); cefuroxime axetil (ceftin);ciprofloxacin (cipro); aminacrine hydrochloride; benzethonium chloride:bithionolate sodium; bromchlorenone; carbamide peroxide; cetalkoniumchloride; cetylpyridinium chloride: chlorhexidine hydrochloride;clioquinol; domiphen bromide; fenticlor; fludazonium chloride; fuchsin,basic; furazolidone; gentian violet; halquinols; hexachlorophene:hydrogen peroxide; ichthammol; imidecyl iodine; iodine; isopropylalcohol; mafenide acetate; meralein sodium; mercufenol chloride;mercury, ammoniated; methylbenzethonium chloride; nitrofurazone;nitromersol; octenidine hydrochloride; oxychlorosene; oxychlorosenesodium; parachlorophenol, camphorated; potassium permanganate;povidone-iodine; sepazonium chloride; silver nitrate; sulfadiazine,silver; symclosene; thimerfonate sodium; thimerosal: troclosenepotassium.

Antifungal (antibiotics) include: polyenes such as Amphotericin-B,candicidin, dermostatin, filipin, fungichromin, hachimycin, hamycin,lucensomycin, mepartricin, natamycin, nystatin, pecilocin, perimycin;and others, such as azaserine, griseofulvin, oligomycins, pyrrolnitrin,siccanin, tubercidin and viridin. Antifungal synthetics include:allylamines such as naftifine and terbinafine; imidazoles such asbifonazole, butoconazole, chlordantoin, chlormidazole, cloconazole,clotrimazole, econazole, enilconazole, fenticonazole, isoconazole,ketoconazole, miconazole, omoconazole, oxiconazole nitrate, sulconazoleand tioconazole; triazoles such as fluconazole, itraconazole,terconazole. Others include acrisorcin, amorolfine, biphenamine,bromosalicylchloranilide, buclosamide, chlophenesin, ciclopirox,cloxyquin, coparaffinate, diamthazole, dihydrochloride, exalamide,flucytosine, halethazole, hexetidine, loflucarban, nifuratel, potassiumiodide, propionates, propionic acid, pyrithione, salicylanilide,sulbentine, tenonitrozole, tolciclate, tolindate, tolnaftate, tricetin,ujothion, and undecylenic acid. Antifungals also include theechinocandin class class or antifungals; including caspofungin,micafungin, anidulafungin, aminocandin, and the like.

Vasoconstrictors include, but are not limited to, epinephrine,norepinephrine, pseudoephedrine, phenylephrine, oxymetazoline,propylhexedrine, naphazoline, tetrahydrolozine, xylometazonline,ethylnorepinephrine, methoxamine, phenylhexedrine, mephentermine,metaraminol, dopamine, dipivefrin, norphedrine and ciraxzoline may beadvantageously used in the compositions and methods herein. Use of suchshould aid in reducing systemic delivery of the active antihyperalgesicagent.

The pharmaceutical preparations of the invention, when used alone or incocktails, are administered in therapeutically effective amounts. Atherapeutically effective amount will be determined by the parametersdiscussed below; but, in any event, is that amount which establishes alevel of the drug(s) effective for treating a subject, such as a humansubject, having one of the conditions described herein. An effectiveamount means that amount alone or with multiple doses, or the rate ofdelivery necessary to delay the onset of, lessen the severity of, orinhibit completely, lessen the progression of, or halt altogether theonset or progression of the condition being treated or a symptomassociated therewith. In the case of diarrhea, an effective amount canbe, for example, that amount which results in one or more of thefollowing: 1) decreasing the frequency of bowel movements; 2) increasingthe consistency of the stool, and/or 3) decreasing the stool volume toless than 200 g per day. In one embodiment, an effective amount is anamount that results in 3 or less per bowel movments per day, preferably2 or less per day, more preferably 1 bowel movement per day. In certaininstances, the amount is sufficient to decrease bowel movements within12 hours of administration of the MNTX, 10 hours, 8 hours, 6 hours, 4hours, 2 hours, 1 hour and even immediately upon administration,depending upon the mode of administration. Intravenous administrationcan produce an immediate effect. In restoring gastrointestinal function,an effective amount can be, for example, that amount necessary toincrease oral-cecal transit time. For management or treatment of pain,an effective amount can be, for example, that amount to sufficient tomake a subject more comfortable as determined by subjective criteria,objective criteria or both. In the case of peripheral hyperalgesia, aneffective amount can be, for example, that amount which relieves asymptom of peripheral hyperalgesia such as hypersensitivity to pain orpruritis. For the prevention or treatment of inflammation, an effectiveamount can be, for example, the amount sufficient to reduce or lessenthe redness, swelling, or tissue damage associated with the inflammationor to increase the mobility of an affected area such as a joint. Whenadministered to a subject, effective amounts will depend, of course, onthe particular condition being treated; the severity of the condition;individual patient parameters including age, physical condition, sizeand weight; concurrent treatment; frequency of treatment; and the modeof administration. These factors are well known to those of ordinaryskill in the art and can be addressed with no more than routineexperimentation.

Generally, oral doses of S-MNTX will be from about 0.05 to about 40mg/kg, from 0.05 to about 20.0 mg/kg, from about 0.05 to about 10 mg/kg,or from about 0.05 to about 5 mg/kg body weight per day. Generally,parenteral administration, including intravenous and subcutaneousadministration, will be from about 0.001 to 1.0 mg/kg, from about 0.01to 1.0 mg/kg, or from about 0.1 to 1.0 mg/kg body weight depending onwhether administration is as a bolus or is spread out over time such aswith an I.V. drip. It is expected that doses ranging from about 0.05 to0.5 mg/kg body weight will yield the desired results. Dosage may beadjusted appropriately to achieve desired drug levels, local orsystemic, depending on the mode of administration. For example, it isexpected that the dosage for oral administration of the S-MNTX in anenterically-coated formulation would be lower than in an immediaterelease oral formulation. In the event that the response in a patient isinsufficient at such doses, even higher doses (or effectively higherdosage by a different, more localized delivery route) may be employed tothe extent that the patient tolerance permits. Multiple doses per dayare contemplated to achieve appropriate systemic levels of compounds.Appropriate systemic levels can be determined by, for example,measurement of the patient's peak or sustained plasma level of the drug.“Dose” and “dosage” are used interchangeably herein.

A variety of administration routes are available. The particular modeselected will depend, of course, upon the particular combination ofdrugs selected, the severity of the condition being treated, orprevented, the condition of the patient, and the dosage required fortherapeutic efficacy. The methods of this invention, generally speaking,may be practiced using any mode of administration that is medicallyacceptable, meaning any mode that produces effective levels of theactive compounds without causing clinically unacceptable adverseeffects. Such modes of administration include oral, rectal, topical,transdermal, sublingual, intravenous infusion, pulmonary,intra-arterial, intra-adipose tissue, intra-lymphatic, intramuscular,intracavity, aerosol, aural (e.g., via eardrops), intranasal,inhalation, intra-articular, needleless injection, subcutaneous orintradermal (e.g., transdermal) delivery. For continuous infusion, apatient-controlled analgesia (PCA) device or an implantable drugdelivery device may be employed. Oral, rectal, or topical administrationmay be important for prophylactic or long-term treatment. Preferredrectal modes of delivery include administration as a suppository orenema wash.

The pharmaceutical preparations may conveniently be presented in unitdosage form and may be prepared by any of the methods well known in theart of pharmacy. All methods include the step of bringing the compoundsof the invention into association with a carrier which constitutes oneor more accessory ingredients. In general, the compositions are preparedby uniformly and intimately bringing the compounds of the invention intoassociation with a liquid carrier, a finely divided solid carrier, orboth, and then, if necessary, shaping the product.

When administered, the pharmaceutical preparations of the invention areapplied in pharmaceutically acceptable compositions. Such preparationsmay routinely contain salts, buffering agents, preservatives, compatiblecarriers, lubricants, and optionally other therapeutic ingredients. Whenused in medicine the salts should be pharmaceutically acceptable, butnon-pharmaceutically acceptable salts may conveniently be used toprepare pharmaceutically acceptable salts thereof and are not excludedfrom the scope of the invention. Such pharmacologically andpharmaceutically acceptable salts include, but are not limited to, thoseprepared from the following acids: hydrochloric, hydrobromic, sulfuric,nitric, phosphoric, maleic, acetic, salicylic, p-toluenesulfonic,tartaric, citric, methanesulfonic, formic, succinic,naphthalene-2-sulfonic, pamoic, 3-hydroxy-2-naphthalenecarboxylic, andbenzene sulfonic.

It should be understood that when referring to MNTX, R- and S-MNTX, andtherapeutic agent(s) of the invention, it is meant to encompass salts ofthe same. Such salts are of a variety well known to those or ordinaryskill in the art. When used in pharmaceutical preparations, the saltspreferably are pharmaceutically-acceptable for use in humans. Bromide isan example of one such salt.

The pharmaceutical preparations of the present invention may include orbe diluted into a pharmaceutically-acceptable carrier. The term“pharmaceutically-acceptable carrier” as used herein means one or morecompatible solid or liquid fillers, diluents or encapsulating substanceswhich are suitable for administration to a human or other mammal such asnon-human primate, a dog, cat, horse, cow, sheep, pig, or goat. The term“carrier” denotes an organic or inorganic ingredient, natural orsynthetic, with which the active ingredient is combined to facilitatethe application. The carriers are capable of being commingled with thepreparations of the present invention, and with each other, in a mannersuch that there is no interaction which would substantially impair thedesired pharmaceutical efficacy or stability. Carrier formulationssuitable for oral administration, for suppositories, and for parenteraladministration, etc., can be found in Remington's PharmaceuticalSciences, Mack Publishing Company, Easton, Pa.

Aqueous formulations may include a chelating agent, a buffering agent,an anti-oxidant and, optionally, an isotonicity agent, preferably pHadjusted to between 3.0 and 3.5. Examples of such formulations that arestable to autoclaving and long term storage are described in co-pendingU.S. application Ser. No. 10/821,811, entitled “PharmaceuticalFormulation.”

Chelating agents include, for example, ethylenediaminetetraacetic acid(EDTA) and derivatives thereof, citric acid and derivatives thereof,niacinamide and derivatives thereof, sodium desoxycholate andderivatives thereof, and L-glutamic acid, N, N-diacetic acid andderivatives thereof.

Buffering agents include those selected from the group consisting ofcitric acid, sodium citrate, sodium acetate, acetic acid, sodiumphosphate and phosphoric acid, sodium ascorbate, tartaric acid, maleicacid, glycine, sodium lactate, lactic acid, ascorbic acid, imidazole,sodium bicarbonate and carbonic acid, sodium succinate and succinicacid, histidine, and sodium benzoate and benzoic acid, or combinationsthereof.

Antioxidants include those selected from the group consisting of anascorbic acid derivative, butylated hydroxy anisole, butylated hydroxytoluene, alkyl gallate, sodium meta-bisulfite, sodium bisulfite, sodiumdithionite, sodium thioglycollate acid, sodium formaldehyde sulfoxylate,tocopheral and derivatives thereof, monothioglycerol, and sodiumsulfite. The preferred antioxidant is monothioglycerol.

Isotonicity agents include those selected from the group consisting ofsodium chloride, mannitol, lactose, dextrose, glycerol, and sorbitol.

Preservatives that can be used with the present compositions includebenzyl alcohol, parabens, thimerosal, chlorobutanol and preferablybenzalkonium chloride. Typically, the preservative will be present in acomposition in a concentration of up to about 2% by weight. The exactconcentration of the preservative, however, will vary depending upon theintended use and can be easily ascertained by one skilled in the art.

The compounds of the invention can be prepared in lyophilizedcompositions, preferably in the presence of a cryoprotecting agent suchas mannitol, or lactose, sucrose, polyethylene glycol, and polyvinylpyrrolidines. Cryoprotecting agents which result in a reconstitution pHof 6.0 or less are preferred. The invention therefore provides alyophilized preparation of therapeutic agent(s) of the invention. Thepreparation can contain a cryoprotecting agent, such as mannitol orlactose, which is preferably neutral or acidic in water.

Oral, parenteral and suppository formulations of agents are well knownand commercially available. The therapeutic agent(s) of the inventioncan be added to such well known formulations. It can be mixed togetherin solution or semi-solid solution in such formulations, can be providedin a suspension within such formulations or could be contained inparticles within such formulations.

A product containing therapeutic agent(s) of the invention and,optionally, one or more other active agents can be configured as an oraldosage. The oral dosage may be a liquid, a semisolid or a solid. Anopioid may optionally be included in the oral dosage. The oral dosagemay be configured to release the therapeutic agent(s) of the inventionbefore, after or simultaneously with the other agent (and/or theopioid). The oral dosage may be configured to have the therapeuticagent(s) of the invention and the other agents release completely in thestomach, release partially in the stomach and partially in theintestine, in the intestine, in the colon, partially in the stomach, orwholly in the colon. The oral dosage also may be configured whereby therelease of the therapeutic agent(s) of the invention is confined to thestomach or intestine while the release of the other active agent is notso confined or is confined differently from the therapeutic agent(s) ofthe invention. For example, the therapeutic agent(s) of the inventionmay be an enterically coated core or pellets contained within a pill orcapsule that releases the other agent first and releases the therapeuticagent(s) of the invention only after the therapeutic agent(s) of theinvention passes through the stomach and into the intestine. Thetherapeutic agent(s) of the invention also can be in a sustained releasematerial, whereby the therapeutic agent(s) of the invention is releasedthroughout the gastrointestinal tract and the other agent is released onthe same or a different schedule. The same objective for therapeuticagent(s) of the invention release can be achieved with immediate releaseof therapeutic agent(s) of the invention combined with enteric coatedtherapeutic agent(s) of the invention. In these instances, the otheragent could be released immediately in the stomach, throughout thegastrointestinal tract or only in the intestine.

The materials useful for achieving these different release profiles arewell known to those of ordinary skill in the art. Immediate release isobtainable by conventional tablets with binders which dissolve in thestomach. Coatings which dissolve at the pH of the stomach or whichdissolve at elevated temperatures will achieve the same purpose. Releaseonly in the intestine is achieved using conventional enteric coatingssuch as pH sensitive coatings which dissolve in the pH environment ofthe intestine (but not the stomach) or coatings which dissolve overtime. Release throughout the gastrointestinal tract is achieved by usingsustained-release materials and/or combinations of the immediate releasesystems and sustained and/or delayed intentional release systems (e.g.,pellets which dissolve at different pHs).

In the event that it is desirable to release the therapeutic agent(s) ofthe invention first, the therapeutic agent(s) of the invention could becoated on the surface of the controlled release formulation in anypharmaceutically acceptable carrier suitable for such coatings and forpermitting the release of the therapeutic agent(s) of the invention,such as in a temperature sensitive pharmaceutically acceptable carrierused for controlled release routinely. Other coatings which dissolvewhen placed in the body are well known to those of ordinary skill in theart.

The therapeutic agent(s) of the invention also may be mixed throughout acontrolled release formulation, whereby it is released before, after orsimultaneously with another agent. The therapeutic agent(s) of theinvention may be free, that is, solubilized within the material of theformulation. The therapeutic agent(s) of the invention also may be inthe form of vesicles, such as wax coated micropellets dispersedthroughout the material of the formulation. The coated pellets can befashioned to immediately release the therapeutic agent(s) of theinvention based on temperature, pH or the like. The pellets also can beconfigured so as to delay the release of the therapeutic agent(s) of theinvention, allowing the other agent a period of time to act before thetherapeutic agent(s) of the invention exerts its effects. Thetherapeutic agent(s) of the invention pellets also can be configured torelease the therapeutic agent(s) of the invention in virtually anysustained release pattern, including patterns exhibiting first orderrelease kinetics or sigmoidal order release kinetics using materials ofthe prior art and well known to those of ordinary skill in the art.

The therapeutic agent(s) of the invention also can be contained within acore within the controlled release formulation. The core may have anyone or any combination of the properties described above in connectionwith the pellets. The therapeutic agent(s) of the invention may be, forexample, in a core coated with a material, dispersed throughout amaterial, coated onto a material or adsorbed into or throughout amaterial.

It should be understood that the pellets or core may be of virtually anytype. They may be drug coated with a release material, drug interspersedthroughout material, drug adsorbed into a material, and so on. Thematerial may be erodible or nonerodible.

The therapeutic agent(s) of the invention, may be provided in particles.Particles as used herein means nano or microparticles (or in someinstances larger) which can consist in whole or in part of thetherapeutic agent(s) of the inventions or the other agents as describedherein. The particles may contain the therapeutic agent(s) in a coresurrounded by a coating, including, but not limited to, an entericcoating. The therapeutic agent(s) also may be dispersed throughout theparticles. The therapeutic agent(s) also may be adsorbed into theparticles. The particles may be of any order release kinetics, includingzero order release, first order release, second order release, delayedrelease, sustained release, immediate release, and any combinationthereof, etc. The particle may include, in addition to the therapeuticagent(s), any of those materials routinely used in the art of pharmacyand medicine, including, but not limited to, erodible, nonerodible,biodegradable, or nonbiodegradable material or combinations thereof. Theparticles may be microcapsules which contain the antagonist in asolution or in a semi-solid state. The particles may be of virtually anyshape.

Both non-biodegradable and biodegradable polymeric materials can be usedin the manufacture of particles for delivering the therapeutic agent(s).Such polymers may be natural or synthetic polymers. The polymer isselected based on the period of time over which release is desired.Bioadhesive polymers of particular interest include bioerodiblehydrogels described by H. S. Sawhney, C. P. Pathak and J. A. Hubell inMacromolecules, (1993) 26:581-587, the teachings of which areincorporated herein. These include polyhyaluronic acids, casein,gelatin, glutin, polyanhydrides, polyacrylic acid, alginate, chitosan,poly(methyl methacrylates), poly(ethyl methacrylates),poly(butylmethacrylate), poly(isobutyl methacrylate),poly(hexylmethacrylate), poly(isodecyl methacrylate), poly(laurylmethacrylate), poly(phenyl methacrylate), poly(methyl acrylate),poly(isopropyl acrylate), poly(isobutyl acrylate), and poly(octadecylacrylate).

The therapeutic agent(s) may be contained in controlled release systems.The term “controlled release” is intended to refer to anydrug-containing formulation in which the manner and profile of drugrelease from the formulation are controlled. This refers to immediate aswell as nonimmediate release formulations, with nonimmediate releaseformulations including but not limited to sustained release and delayedrelease formulations. The term “sustained release” (also referred to as“extended release”) is used in its conventional sense to refer to a drugformulation that provides for gradual release of a drug over an extendedperiod of time, and that preferably, although not necessarily, resultsin substantially constant blood levels of a drug over an extended timeperiod. The term “delayed release” is used in its conventional sense torefer to a drug formulation in which there is a time delay betweenadministration of the formulation and the release of the drug therefrom.“Delayed release” may or may not involve gradual release of drug over anextended period of time, and thus may or may not be “sustained release.”These formulations may be for any mode of administration.

Delivery systems specific for the gastrointestinal tract are roughlydivided into three types: the first is a delayed release system designedto release a drug in response to, for example, a change in pH; thesecond is a timed-release system designed to release a drug after apredetermined time; and the third is a microflora enzyme system makinguse of the abundant enterobacteria in the lower part of thegastrointestinal tract (e.g., in a colonic site-directed releaseformulation).

An example of a delayed release system is one that uses, for example, anacrylic or cellulosic coating material and dissolves on pH change.Because of ease of preparation, many reports on such “enteric coatings”have been made. In general, an enteric coating is one which passesthrough the stomach without releasing substantial amounts of drug in thestomach (i.e., less than 10% release, 5% release and even 1% release inthe stomach) and sufficiently disintegrating in the intestinal tract (bycontact with approximately neutral or alkaline intestine juices) toallow the transport (active or passive) of the active agent through thewalls of the intestinal tract.

Various in vitro tests for determining whether or not a coating isclassified as an enteric coating have been published in thepharmacopoeia of various countries. A coating which remains intact forat least 2 hours, in contact with artificial gastric juices such as HClof pH 1 at 36 to 38° C. and thereafter disintegrates within 30 minutesin artificial intestinal juices such as a KH₂PO₄ buffered solution of pH6.8 is one example. One such well known system is EUDRAGIT material,commercially available and reported on by Behringer, ManchesterUniversity, Saale Co., and the like. Enteric coatings are discussedfurther, below.

A timed release system is represented by Time Erosion System (TES) byFujisawa Pharmaceutical Co., Ltd. and Pulsincap by R. P. Scherer.According to these systems, the site of drug release is decided by thetime of transit of a preparation in the gastrointestinal tract. Sincethe transit of a preparation in the gastrointestinal tract is largelyinfluenced by the gastric emptying time, some time release systems arealso enterically coated.

Systems making use of the enterobacteria can be classified into thoseutilizing degradation of azoaromatic polymers by an azo reductaseproduced from enterobacteria as reported by the group of Ohio University(M. Saffran, et al., Science, Vol. 233: 1081 (1986)) and the group ofUtah University (J. Kopecek, et al., Pharmaceutical Research, 9(12),1540-1545 (1992)); and those utilizing degradation of polysaccharides bybeta-galactosidase of enterobacteria as reported by the group of HebrewUniversity (unexamined published Japanese patent application No. 5-50863based on a PCT application) and the group of Freiberg University (K. H.Bauer et al., Pharmaceutical Research, 10(10), S218 (1993)). Inaddition, the system using chitosan degradable by chitosanase by TeikokuSeiyaku K. K. (unexamined published Japanese patent application No.4-217924 and unexamined published Japanese patent application No.4-225922) is also included.

The enteric coating is typically, although not necessarily, a polymericmaterial. Preferred enteric coating materials comprise bioerodible,gradually hydrolyzable and/or gradually water-soluble polymers. The“coating weight,” or relative amount of coating material per capsule,generally dictates the time interval between ingestion and drug release.Any coating should be applied to a sufficient thickness such that theentire coating does not dissolve in the gastrointestinal fluids at pHbelow about 5, but does dissolve at pH about 5 and above. It is expectedthat any anionic polymer exhibiting a pH-dependent solubility profilecan be used as an enteric coating in the practice of the presentinvention. The selection of the specific enteric coating material willdepend on the following properties: resistance to dissolution anddisintegration in the stomach; impermeability to gastric fluids anddrug/carrier/enzyme while in the stomach; ability to dissolve ordisintegrate rapidly at the target intestine site; physical and chemicalstability during storage; non-toxicity; ease of application as a coating(substrate friendly); and economical practicality.

Suitable enteric coating materials include, but are not limited to:cellulosic polymers such as cellulose acetate phthalate, celluloseacetate trimellitate, hydroxypropylmethyl cellulose phthalate,hydroxypropyhmethyl cellulose succinate and carboxymethylcellulosesodium; acrylic acid polymers and copolymers, preferably formed fromacrylic acid, methacrylic acid, methyl acrylate, ammoniummethylacrylate, ethyl acrylate, methyl methacrylate and/or ethylmethacrylate (e.g., those copolymers sold under the trade nameEUDRAGIT); vinyl polymers and copolymers such as polyvinyl acetate,polyvinylacetate phthalate, vinylacetate crotonic acid copolymer, andethylene-vinyl acetate copolymers; and shellac (purified lac).Combinations of different coating materials may also be used. Well knownenteric coating material for use herein are those acrylic acid polymersand copolymers available under the trade name EUDRAGIT from Rohm Pharma(Germany). The EUDRAGIT series E, L, S, RL, RS and NE copolymers areavailable as solubilized in organic solvent, as an aqueous dispersion,or as a dry powder. The EUDRAGIT series RL, NE, and RS copolymers areinsoluble in the gastrointestinal tract but are permeable and are usedprimarily for extended release. The EUDRAGIT series E copolymersdissolve in the stomach. The EUDRAGIT series L, L-30D and S copolymersare insoluble in stomach and dissolve in the intestine, and are thusmost preferred herein.

A particular methacrylic copolymer is EUDRAGIT L, particularly L-30D andEUDRAGIT L 100-55. In EUDRAGIT L-30D, the ratio of free carboxyl groupsto ester groups is approximately 1:1. Further, the copolymer is known tobe insoluble in gastrointestinal fluids having pH below 5.5, generally1.5-5.5, i.e., the pH generally present in the fluid of the uppergastrointestinal tract, but readily soluble or partially soluble at pHabove 5.5, i.e., the pH generally present in the fluid of lowergastrointestinal tract. Another particular methacrylic acid polymer isEUDRAGIT S, which differs from EUDRAGIT L-30D in that the ratio of freecarboxyl groups to ester groups is approximately 1:2. EUDRAGIT S isinsoluble at pH below 5.5, but unlike EUDRAGIT L-30D, is poorly solublein gastrointestinal fluids having a pH in the range of 5.5 to 7.0, suchas in the small intestine. This copolymer is soluble at pH 7.0 andabove, i.e., the pH generally found in the colon. EUDRAGIT S can be usedalone as a coating to provide drug delivery in the large intestine.Alternatively, EUDRAGIT S, being poorly soluble in intestinal fluidsbelow pH 7, can be used in combination with EUDRAGIT L-30D, soluble inintestinal fluids above pH 5.5, in order to provide a delayed releasecomposition which can be formulated to deliver the active agent tovarious segments of the intestinal tract. The more EUDRAGIT L-30D used,the more proximal release and delivery begins, and the more EUDRAGIT Sused, the more distal release and delivery begins. It will beappreciated by those skilled in the art that both EUDRAGIT L-30D andEUDRAGIT S can be replaced with other pharmaceutically acceptablepolymers having similar pH solubility characteristics. In certainembodiments of the invention, the preferred enteric coating isACRYL-EZE™ (methacrylic acid co-polymer type C; Colorcon, West Point,Pa.).

The enteric coating provides for controlled release of the active agent,such that drug release can be accomplished at some generally predictablelocation. The enteric coating also prevents exposure of the therapeuticagent and carrier to the epithelial and mucosal tissue of the buccalcavity, pharynx, esophagus, and stomach, and to the enzymes associatedwith these tissues. The enteric coating therefore helps to protect theactive agent, carrier and a patient's internal tissue from any adverseevent prior to drug release at the desired site of delivery.Furthermore, the coated material of the present invention allowsoptimization of drug absorption, active agent protection, and safety.Multiple enteric coatings targeted to release the active agent atvarious regions in the gastrointestinal tract would enable even moreeffective and sustained improved delivery throughout thegastrointestinal tract.

The coating can, and usually does, contain a plasticizer to prevent theformation of pores and cracks that would permit the penetration of thegastric fluids. Suitable plasticizers include, but are not limited to,triethyl citrate (Citroflex 2), triacetin (glyceryl triacetate), acetyltriethyl citrate (Citroflec A2), Carbowax 400 (polyethylene glycol 400),diethyl phthalate, tributyl citrate, acetylated monoglycerides,glycerol, fatty acid esters, propylene glycol, and dibutyl phthalate. Inparticular, a coating comprised of an anionic carboxylic acrylic polymerwill usually contain approximately 10% to 25% by weight of aplasticizer, particularly dibutyl phthalate, polyethylene glycol,triethyl citrate and triacetin. The coating can also contain othercoating excipients such as detackifiers, antifoaming agents, lubricants(e.g., magnesium stearate), and stabilizers (e.g.,hydroxypropylcellulose, acids and bases) to solubilize or disperse thecoating material, and to improve coating performance and the coatedproduct.

The coating can be applied to particles of the therapeutic agent(s),tablets of the therapeutic agent(s), capsules containing the therapeuticagent(s) and the like, using conventional coating methods and equipment.For example, an enteric coating can be applied to a capsule using acoating pan, an airless spray technique, fluidized bed coatingequipment, or the like. Detailed information concerning materials,equipment and processes for preparing coated dosage forms may be foundin Pharmaceutical Dosage Forms: Tablets, eds. Lieberman et al. (NewYork: Marcel Dekker, Inc., 1989), and in Ansel et al., PharmaceuticalDosage Forms and Drug Delivery Systems, 6th Ed. (Media, Pa.: Williams &Wilkins, 1995). The coating thickness, as noted above, must besufficient to ensure that the oral dosage form remains intact until thedesired site of topical delivery in the lower intestinal tract isreached.

In another embodiment, drug dosage forms are provided that comprise anenterically coated, osmotically activated device housing a formulationof the invention. In this embodiment, the drug-containing formulation isencapsulated in a semipermeable membrane or barrier containing a smallorifice. As known in the art with respect to so-called “osmotic pump”drug delivery devices, the semipermeable membrane allows passage ofwater in either direction, but not drug. Therefore, when the device isexposed to aqueous fluids, water will flow into the device due to theosmotic pressure differential between the interior and exterior of thedevice. As water flows into the device, the drug-containing formulationin the interior will be “pumped” out through the orifice. The rate ofdrug release will be equivalent to the inflow rate of water times thedrug concentration. The rate of water influx and drug efflux can becontrolled by the composition and size of the orifice of the device.Suitable materials for the semipermeable membrane include, but are notlimited to, polyvinyl alcohol, polyvinyl chloride, semipermeablepolyethylene glycols, semipermeable polyurethanes, semipermeablepolyamides, semipermeable sulfonated polystyrenes and polystyrenederivatives; semipermeable poly(sodium styrenesulfonate), semipermeablepoly(vinylbenzyltrimethylammonium chloride), and cellulosic polymerssuch as cellulose acetate, cellulose diacetate, cellulose triacetate,cellulose propionate, cellulose acetate propionate, cellulose acetatebutyrate, cellulose trivalerate, cellulose trilmate, cellulosetripalmitate, cellulose trioctanoate, cellulose tripropionate, cellulosedisuccinate, cellulose dipalmitate, cellulose dicylate, celluloseacetate succinate, cellulose propionate succinate, cellulose acetateoctanoate, cellulose valerate palmitate, cellulose acetate heptanate,cellulose acetaldehyde dimethyl acetal, cellulose acetateethylcarbamate, cellulose acetate methylcarbamate, cellulosedimethylaminoacetate and ethylcellulose.

In another embodiment, drug dosage forms are provided that comprise asustained release coated device housing a formulation of the invention.In this embodiment, the drug-containing formulation is encapsulated in asustained release membrane or film. The membrane may be semipermeable,as described above. A semipermeable membrane allows for the passage ofwater inside the coated device to dissolve the drug. The dissolved drugsolution diffuses out through the semipermeable membrane. The rate ofdrug release depends upon the thickness of the coated film and therelease of drug can begin in any part of the GI tract Suitable membranematerials for such a membrane include ethylcellulose.

In another embodiment, drug dosage forms are provided that comprise asustained release device housing a formulation of the invention. In thisembodiment, the drug-containing formulation is uniformly mixed with asustained release polymer. These sustained release polymers are highmolecular weight water-soluble polymers, which when in contact withwater, swell and create channels for water to diffuse inside anddissolve the drug. As the polymers swell and dissolve in water, more ofdrug is exposed to water for dissolution. Such a system is generallyreferred to as sustained release matrix. Suitable materials for such adevice include hydropropyl methylcellulose, hydroxypropyl cellulose,hydroxyethyl cellulose and methyl cellulose.

In another embodiment, drug dosage forms are provided that comprise anenteric coated device housing a sustained release formulation of theinvention. In this embodiment, the drug containing product describedabove is coated with an enteric polymer. Such a device would not releaseany drug in the stomach and when the device reaches the intestine, theenteric polymer is first dissolved and only then would the drug releasebegin. The drug release would take place in a sustained release fashion.

Enterically coated, osmotically activated devices can be manufacturedusing conventional materials, methods and equipment. For example,osmotically activated devices may be made by first encapsulating, in apharmaceutically acceptable soft capsule, a liquid or semi-solidformulation of the compounds of the invention as described previously.This interior capsule is then coated with a semipermeable membranecomposition (comprising, for example, cellulose acetate and polyethyleneglycol 4000 in a suitable solvent such as a methylene chloride-methanoladmixture), for example using an air suspension machine, until asufficiently thick laminate is formed, e.g., around 0.05 mm. Thesemipermeable laminated capsule is then dried using conventionaltechniques. Then, an orifice having a desired diameter (e.g., about 0.99mm) is provided through the semipermeable laminated capsule wall, using,for example, mechanical drilling, laser drilling, mechanical rupturing,or erosion of an erodible element such as a gelatin plug. Theosmotically activated device may then be enterically coated aspreviously described. For osmotically activated devices containing asolid carrier rather than a liquid or semi-solid carrier, the interiorcapsule is optional; that is, to the semipermeable membrane may beformed directly around the carrier-drug composition. However, preferredcarriers for use in the drug-containing formulation of the osmoticallyactivated device are solutions, suspensions, liquids, immiscibleliquids, emulsions, sols, colloids, and oils. Particularly preferredcarriers include, but are not limited to, those used for entericallycoated capsules containing liquid or semisolid drug formulations.

Cellulose coatings include those of cellulose acetate phthalate andtrimellitate; methacrylic acid copolymers, e.g. copolymers derived frommethylacrylic acid and esters thereof, containing at least 40%methylacrylic acid; and especially hydroxypropyl methylcellulosephthalate. Methylacrylates include those of molecular weight above100,000 daltons based on, e.g. methylacrylate and methyl or ethylmethylacrylate in a ratio of about 1:1. Typical products includeEndragit L, e.g. L 100-55, marketed by Rohm GmbH, Darmstadt, Germany.Typical cellulose acetate phthalates have an acetyl content of 17-26%and a phthalate content of from 30-40% with a viscosity of ca. 45-90 cP.Typical cellulose acetate trimellitates have an acetyl content of17-26%, a trimellityl content from 25-35% with a viscosity of ca. 15-20cS. An example of a cellulose acetate trimellitate is the marketedproduct CAT (Eastman Kodak Company, USA). Hydroxypropyl methylcellulosephthalates typically have a molecular weight of from 20,000 to 130,000daltons, a hydroxypropyl content of from 5 to 10%, a methoxy content offrom 18 to 24% and a phthalyl content from 21 to 35%. An example of acellulose acetate phthalate is the marketed product CAP (Eastman Kodak,Rochester N.Y., USA). Examples of hydroxypropyl methylcellulosephthalates are the marketed products having a hydroxypropyl content offrom 6-10%, a methoxy content of from 20-24%, a phthalyl content of from21-27%, a molecular weight of about 84,000 daltons, sold under thetrademark HP50 and available from Shin-Etsu Chemical Co. Ltd., Tokyo,Japan, and having a hydroxypropyl content, a methoxyl content, and aphthalyl content of 5-9%, 18-22% and 27-35%, respectively, and amolecular weight of 78,000 daltons, known under the trademark HP55 andavailable from the same supplier.

The therapeutic agents may be provided in capsules, coated or not. Thecapsule material may be either hard or soft, and as will be appreciatedby those skilled in the art, typically comprises a tasteless, easilyadministered and water soluble compound such as gelatin, starch or acellulosic material. The capsules are preferably sealed, such as withgelatin bands or the like. See, for example, Remington: The Science andPractice of Pharmacy, Nineteenth Edition (Easton, Pa.: Mack PublishingCo., 1995), which describes materials and methods for preparingencapsulated pharmaceuticals.

A product containing therapeutic agent(s) of the invention can beconfigured as a suppository. The therapeutic agent(s) of the inventioncan be placed anywhere within or on the suppository to favorably affectthe relative release of the therapeutic agent(s). The nature of therelease can be zero order, first order, or sigmoidal, as desired.

Suppositories are solid dosage forms of medicine intended foradministration via the rectum. Suppositories are compounded so as tomelt, soften, or dissolve in the body cavity (around 98.6° F.) therebyreleasing the medication contained therein. Suppository bases should bestable, nonirritating, chemically inert, and physiologically inert. Manycommercially available suppositories contain oily or fatty basematerials, such as cocoa butter, coconut oil, palm kernel oil, and palmoil, which often melt or deform at room temperature necessitating coolstorage or other storage limitations. U.S. Pat. No. 4,837,214 to Tanakaet al. describes a suppository base comprised of 80 to 99 percent byweight of a lauric-type fat having a hydroxyl value of 20 or smaller andcontaining glycerides of fatty acids having 8 to 18 carbon atomscombined with 1 to 20 percent by weight diglycerides of fatty acids(which erucic acid is an example of). The shelf life of these type ofsuppositories is limited due to degradation. Other suppository basescontain alcohols, surfactants, and the like which raise the meltingtemperature but also can lead to poor absorption of the medicine andside effects due to irritation of the local mucous membranes (see forexample, U.S. Pat. No. 6,099,853 to Hartelendy et al., U.S. Pat. No.4,999,342 to Ahmad et al., and U.S. Pat. No. 4,765,978 to Abidi et al.).

The base used in the pharmaceutical suppository composition of thisinvention includes, in general, oils and fats comprising triglyceridesas main components such as cacao butter, palm fat, palm kernel oil,coconut oil, fractionated coconut oil, lard and WITEPSOL®, waxes such aslanolin and reduced lanolin; hydrocarbons such as VASELINE®, squalene,squalane and liquid paraffin; long to medium chain fatty acids such ascaprylic acid, lauric acid, stearic acid and oleic acid; higher alcoholssuch as lauryl alcohol, cetanol and stearyl alcohol; fatty acid esterssuch as butyl stearate and dilauryl malonate; medium to long chaincarboxylic acid esters of glycerin such as triolein and tristearin;glycerin-substituted carboxylic acid esters such as glycerin toacetoacetate; and polyethylene glycols and its derivatives such asmacrogols and cetomacrogol. They may be used either singly or incombination of two or more. If desired, the composition of thisinvention may further include a surface-active agent, a coloring agent,etc., which are ordinarily used in suppositories.

The pharmaceutical composition of this invention may be prepared byuniformly mixing predetermined amounts of the active ingredient, theabsorption aid and optionally the base, etc. in a stirrer or a grindingmill, if required at an elevated temperature. The resulting composition,may be formed into a suppository in unit dosage form by, for example,casting the mixture in a mold, or by forming it into a gelatin capsuleusing a capsule filling machine.

The compositions according to the present invention also can beadministered as a nasal spray, nasal drop, suspension, gel, ointment,cream or powder. The administration of a composition can also includeusing a nasal tampon or a nasal sponge containing a composition of thepresent invention.

The nasal delivery systems that can be used with the present inventioncan take various forms including aqueous preparations, non-aqueouspreparations and combinations thereof. Aqueous preparations include, forexample, aqueous gels, aqueous suspensions, aqueous liposomaldispersions, aqueous emulsions, aqueous microemulsions and combinationsthereof. Non-aqueous preparations include, for example, non-aqueousgels, non-aqueous suspensions, non-aqueous liposomal dispersions,non-aqueous emulsions, non-aqueous microemulsions and combinationsthereof. The various forms of the nasal delivery systems can include abuffer to maintain pH, a pharmaceutically acceptable thickening agentand a humectant. The pH of the buffer can be selected to optimize theabsorption of the therapeutic agent(s) across the nasal mucosa.

With respect to the non-aqueous nasal formulations, suitable forms ofbuffering agents can be selected such that when the formulation isdelivered into the nasal cavity of a mammal, selected pH ranges areachieved therein upon contact with, e.g., a nasal mucosa. In the presentinvention, the pH of the compositions should be maintained from about2.0 to about 6.0. It is desirable that the pH of the compositions is onewhich does not cause significant irritation to the nasal mucosa of arecipient upon administration.

The viscosity of the compositions of the present invention can bemaintained at a desired level using a pharmaceutically acceptablethickening agent. Thickening agents that can be used in accordance withthe present invention include methyl cellulose, xanthan gum,carboxymethyl cellulose, hydroxypropyl cellulose, carbomer, polyvinylalcohol, alginates, acacia, chitosans and combinations thereof. Theconcentration of the thickening agent will depend upon the agentselected and the viscosity desired. Such agents can also be used in apowder formulation discussed above.

The compositions of the present invention can also include a humectantto reduce or prevent drying of the mucus membrane and to preventirritation thereof. Suitable humectants that can be used in the presentinvention include sorbitol, mineral oil, vegetable oil and glycerol;soothing agents; membrane conditioners; sweeteners; and combinationsthereof. The concentration of the humectant in the present compositionswill vary depending upon the agent selected.

One or more therapeutic agents may be incorporated into the nasaldelivery system or any other delivery system described herein.

A composition formulated for topical administration may be liquid orsemi-solid (including, for example, a gel, lotion, emulsion, cream,ointment, spray or aerosol) or may be provided in combination with a“finite” carrier, for example, a non-spreading material that retains itsform, including, for example, a patch, bioadhesive, dressing or bandage.It may be aqueous or non-aqueous; it may be formulated as a solution,emulsion, dispersion, a suspension or any other mixture.

Important modes of administration include topical application to theskin, eyes or mucosa. Thus, typical vehicles are those suitable forpharmaceutical or cosmetic application to body surfaces. Thecompositions provided herein may be applied topically or locally tovarious areas in the body of a patient. As noted above, topicalapplication is intended to refer to application to the tissue of anaccessible body surface, such as, for example, the skin (the outerintegument or covering) and the mucosa (the mucous-producing, secretingand/or containing surfaces). Exemplary mucosal surfaces include themucosal surfaces of the eyes, mouth (such as the lips, tongue, gums,cheeks, sublingual and roof of the mouth), larynx, esophagus, bronchial,nasal passages, vagina and rectum/anus; in some embodiments, preferablythe mouth, larynx, esophagus, vagina and rectum/anus; in otherembodiments, preferably the eyes, larynx, esophagus, bronchial, nasalpassages,and vagina and rectum/anus. As noted above, local applicationherein refers to application to a discrete internal area of the body,such as, for example, a joint, soft tissue area (such as muscle, tendon,ligaments, intraocular or other fleshy internal areas), or otherinternal area of the body. Thus, as used herein, local applicationrefers to applications to discrete areas of the body.

With respect to topical and/or local administration of the presentcompositions, desirable efficacy may involve, for example, penetrationof therapeutic agent(s) of the invention into the skin and/or tissue tosubstantially reach a hyperalgesic site to provide desirableanti-hyperalgesic pain relief. The efficacy of the present compositionsmay be about the same as that achieved, for example, with central opiateanalgesics. But, as discussed in detail herein, the efficacy achievedwith therapeutic agent(s) of the invention is preferably obtainedwithout the undesirable effects that are typically associated withcentral opiates including, for example, respiratory depression,sedation, and addiction, as it is believed that therapeutic agent(s) ofthe invention does not cross the blood brain barrier.

Also in certain preferred embodiments, including embodiments thatinvolve aqueous vehicles, the compositions may also contain a glycol,that is, a compound containing two or more hydroxy groups. A glycolwhich is particularly preferred for use in the compositions is propyleneglycol. In these preferred embodiments, the glycol is preferablyincluded in the compositions in a concentration of from greater than 0to about 5 wt. %, based on the total weight of the composition. Morepreferably, the compositions contain from about 0.1 to less than about 5wt. % of a glycol, with from about 0.5 to about 2 wt. % being even morepreferred. Still more preferably, the compositions contain about 1 wt. %of a glycol.

For local internal administration, such as intra-articularadministration, the compositions are preferably formulated as a solutionor a suspension in an aqueous-based medium, such as isotonicallybuffered saline or are combined with a biocompatible support orbioadhesive intended for internal administration.

Lotions, which, for example, may be in the form of a suspension,dispersion or emulsion, contain an effective concentration of one ormore of the compounds. The effective concentration is preferably todeliver an effective amount, typically at a concentration of betweenabout 0.1-50% [by weight] or more of one or more of the compoundsprovided herein. The lotions also contain [by weight] from 1% to 50% ofan emollient and the balance water, a suitable buffer, and other agentsas described above. Any emollients known to those of skill in the art assuitable for application to human skin may be used. These include, butare not limited to, the following: (a) Hydrocarbon oils and waxes,including mineral oil, petrolatum, paraffin, ceresin, ozokerite,microcrystalline wax, polyethylene, and perhydrosqualene. b) Siliconeoils, including dimethylpolysiloxanes, methylphenylpolysiloxanes,water-soluble and alcohol-soluble silicone-glycol copolymers. (c)Triglyceride fats and oils, including those derived from vegetable,animal and marine sources. Examples include, but are not limited to,castor oil, safflower oil, cotton seed oil, corn oil, olive oil, codliver oil, almond oil, avocado oil, palm oil, sesame oil, and soybeanoil. (d) Acetoglyceride esters, such as acetylated monoglycerides. (e)Ethoxylated glycerides, such as ethoxylated glyceryl monstearate. (f)Alkyl esters of fatty acids having 10 to 20 carbon atoms. Methyl,isopropyl and butyl esters of fatty acids are useful herein. Examplesinclude, but are not limited to, hexyl laurate, isohexyl laurate,isohexyl palmitate, isopropyl palmitate, isopropyl myristate, decyloleate, isodecyl oleate, hexadecyl stearate, decyl stearate, isopropylisostearate, diisopropyl adipate, diisohexyl adipate, dihexyldecyladipate, diisopropyl sebacate, lauryl lactate, myristyl lactate, andcetyl lactate. (g) Alkenyl esters of fatty acids having 10 to 20 carbonatoms. Examples thereof include, but are not limited to, oleylmyristate, oleyl stearate, and oleyl oleate. (h) Fatty acids having 9 to22 carbon atoms. Suitable examples include, but are not limited to,pelargonic, lauric, myristic, palmitic, stearic, isostearic,hydroxystearic, oleic, linoleic, ricinoleic, arachidonic, behenic, anderucic acids. (i) Fatty alcohols having 10 to 22 carbon atoms, such as,but not limited to, lauryl, myristyl, cetyl, hexadecyl, stearyl,isostearyl, hydroxystearyl, oleyl, ricinoleyl, behenyl, erucyl, and2-octyl dodecyl alcohols. (j) Fatty alcohol ethers, including, but notlimited to ethoxylated fatty alcohols of 10 to 20 carbon atoms, such as,but are not limited to, the lauryl, cetyl, stearyl, isostearyl, oleyl,and cholesterol alcohols having attached thereto from 1 to 50 ethyleneoxide groups or 1 to 50 propylene oxide groups or mixtures thereof. (k)Ether-esters, such as fatty acid esters of ethoxylated fatty alcohols.(1) Lanolin and derivatives, including, but not limited to, lanolin,lanolin oil, lanolin wax, lanolin alcohols, lanolin fatty acids,isopropyl lanolate, ethoxylated lanolin, ethoxylated lanolin alcohols,ethoxylated cholesterol, propoxylated lanolin alcohols, acetylatedlanolin, acetylated lanolin alcohols, lanolin alcohols linoleate,lanolin alcohols ricinoleate, acetate of lanolin alcohols ricinoleate,acetate of ethoxylated alcohols-esters, hydrogenolysis of lanolin,ethoxylated hydrogenated lanolin, ethoxylated sorbitol lanolin, andliquid and semisolid lanolin absorption bases. (m) polyhydric alcoholsand polyether derivatives, including, but not limited to, propyleneglycol, dipropylene glycol, polypropylene glycol [M.W. 2000-4000],polyoxyethylene polyoxypropylene glycols, polyoxypropylenepolyoxyethylene glycols, glycerol, ethoxylated glycerol, propoxylatedglycerol, sorbitol, ethoxylated sorbitol, hydroxypropyl sorbitol,polyethylene glycol [M.W. 200-6000], methoxy polyethylene glycols 350,550, 750, 2000, 5000, poly(ethylene oxide) homopolymers [M.W.100,000-5,000,000], polyalkylene glycols and derivatives, hexyleneglycol (2-methyl-2,4-pentanediol), 1,3-butylene glycol,1,2,6,-hexanetriol, ethohexadiol USP (2-ethyl-1,3-hexanediol),C.sub.15-C.sub.18 vicinal glycol and polyoxypropylene derivatives oftrimethylolpropane. (n) polyhydric alcohol esters, including, but notlimited to, ethylene glycol mono- and di-fatty acid esters, diethyleneglycol mono- and di-fatty acid esters, polyethylene glycol [M.W.200-6000], mono- and di-fatty esters, propylene glycol mono- anddi-fatty acid esters, polypropylene glycol 2000 monooleate,polypropylene glycol 2000 monostearate, ethoxylated propylene glycolmonostearate, glyceryl mono- and di-fatty acid esters, polyglycerolpoly-fatty acid esters, ethoxylated glyceryl monostearate, 1,3-butyleneglycol monostearate, 1,3-butylene glycol distearate, polyoxyethylenepolyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylenesorbitan fatty acid esters. (o) Wax esters, including, but not limitedto, beeswax, spermaceti, myristyl myristate, and stearyl stearate andbeeswax derivatives, including, but not limited to, polyoxyethylenesorbitol beeswax, which are reaction products of beeswax withethoxylated sorbitol of varying ethylene oxide content that form amixture of ether-esters. (p) Vegetable waxes, including, but not limitedto, carnauba and candelilla waxes. (q) phospholipids, such as lecithinand derivatives. (r) Sterols, including, but not limited to, cholesteroland cholesterol fatty acid esters. (s) Amides, such as fatty acidamides, ethoxylated fatty acid amides, and solid fatty acidalkanolamides.

The lotions further preferably contain [by weight] from 1% to 10%, morepreferably from 2% to 5%, of an emulsifier. The emulsifiers can benonionic, anionic or cationic. Examples of satisfactory nonionicemulsifiers include, but are not limited to, fatty alcohols having 10 to20 carbon atoms, fatty alcohols having 10 to 20 carbon atoms condensedwith 2 to 20 moles of ethylene oxide or propylene oxide, alkyl phenolswith 6 to 12 carbon atoms in the alkyl chain condensed with 2 to 20moles of ethylene oxide, mono- and di-fatty acid esters of ethyleneoxide, mono- and di-fatty acid esters of ethylene glycol where the fattyacid moiety contains from 10 to 20 carbon atoms, diethylene glycol,polyethylene glycols of molecular weight 200 to 6000, propylene glycolsof molecular weight 200 to 3000, glycerol, sorbitol, sorbitan,polyoxyethylene sorbitol, polyoxyethylene sorbitan and hydrophilic waxesters. Suitable anionic emulsifiers include, but are not limited to,the fatty acid soaps, e.g., sodium, potassium and triethanolamine soaps,where the fatty acid moiety contains from 10 to 20 carbon atoms. Othersuitable anionic emulsifiers include, but are not limited to, the alkalimetal, ammonium or substituted ammonium alkyl sulfates, alkylarylsulfonates, and alkyl ethoxy ether sulfonates having 10 to 30 carbonatoms in the alkyl moiety. The alkyl ethoxy ether sulfonates containfrom 1 to 50 ethylene oxide units. Among satisfactory cationicemulsifiers are quaternary ammonium, morpholinium and pyridiniumcompounds. Certain of the emollients described in preceding paragraphsalso have emulsifying properties. When a lotion is formulated containingsuch an emollient, an additional emulsifier is not needed, though it canbe included in the composition.

The balance of the lotion is water or a C₂ or C₃ alcohol, or a mixtureof water and the alcohol. The lotions are formulated by simply admixingall of the components together. Preferably the compound, such asloperamide, is dissolved, suspended or otherwise uniformly dispersed inthe mixture.

Other conventional components of such lotions may be included. One suchadditive is a thickening agent at a level from 1% to 10% by weight ofthe composition. Examples of suitable thickening agents include, but arenot limited to: cross-linked carboxypolymethylene polymers, ethylcellulose, polyethylene glycols, gum tragacanth, gum kharaya, xanthangums and bentonite, hydroxyethyl cellulose, and hydroxypropyl cellulose.

Creams can be formulated to contain a concentration effective to deliveran effective amount of therapeutic agent(s) of the invention to thetreated tissue, typically at between about 0.1%, preferably at greaterthan 1% up to and greater than 50%, preferably between about 3% and 50%,more preferably between about 5% and 15% therapeutic agent(s) of theinvention. The creams also contain from 5% to 50%, preferably from 10%to 25%, of an emollient and the remainder is water or other suitablenon-toxic carrier, such as an isotonic buffer. The emollients, asdescribed above for the lotions, can also be used in the creamcompositions. The cream may also contain a suitable emulsifier, asdescribed above. The emulsifier is included in the composition at alevel from 3% to 50%, preferably from 5% to 20%.

These compositions that are formulated as solutions or suspensions maybe applied to the skin, or, may be formulated as an aerosol or foam andapplied to the skin as a spray-on. The aerosol compositions typicallycontain [by weight] from 25% to 80%, preferably from 30% to 50%, of asuitable propellant. Examples of such propellants are the chlorinated,fluorinated and chlorofluorinated lower molecular weight hydrocarbons.Nitrous oxide, carbon dioxide, butane, and propane are also used aspropellant gases. These propellants are used as understood in the art ina quantity and under a pressure suitable to expel the contents of thecontainer.

Suitably prepared solutions and suspensions may also be topicallyapplied to the eyes and mucosa. Solutions, particularly those intendedfor ophthalmic use, may be formulated as 0.01%-10% isotonic solutions,pH about 5-7, with appropriate salts, and preferably containing one ormore of the compounds herein at a concentration of about 0.1%,preferably greater than 1%, up to 50% or more. Suitable ophthalmicsolutions are known [see, e.g., U.S. Pat. No. 5,116,868, which describestypical compositions of ophthalmic irrigation solutions and solutionsfor topical application]. Such solutions, which have a pH adjusted toabout 7.4, contain, for example, 90-100 mM sodium chloride, 4-6 mMdibasic potassium phosphate, 4-6 mM dibasic sodium phosphate, 8-12 mMsodium citrate, 0.5-1.5 mM magnesium chloride, 1.5-2.5 mM calciumchloride, 15-25 mM sodium acetate, 10-20 mM D.L.-sodium,.β-hydroxybutyrate and 5-5.5 mM glucose.

Gel compositions can be formulated by simply admixing a suitablethickening agent to the previously described solution or suspensioncompositions. Examples of suitable thickening agents have beenpreviously described with respect to the lotions.

The gelled compositions contain an effective amount of therapeuticagent(s) of the invention, typically at a concentration of between about0.1-50% by weight or more of one or more of the compounds providedherein.; from 5% to 75%, preferably from 10% to 50%, of an organicsolvent as previously described; from 0.5% to 20%, preferably from 1% to10% of the thickening agent; the balance being water or other aqueous ornon-aqueous carrier, such as, for example, an organic liquid, or amixture of carriers.

The formulations can be constructed and arranged to create steady stateplasma levels. Steady state plasma concentrations can be measured usingHPLC techniques, as are known to those of skill in the art. Steady stateis achieved when the rate of drug availability is equal to the rate ofdrug elimination from the circulation. In typical therapeutic settings,the therapeutic agent(s) of the invention will be administered topatients either on a periodic dosing regimen or with a constant infusionregimen. The concentration of drug in the plasma will tend to riseimmediately after the onset of administration and will tend to fall overtime as the drug is eliminated from the circulation by means ofdistribution into cells and tissues, by metabolism, or by excretion.Steady state will be obtained when the mean drug concentration remainsconstant over time. In the case of intermittent dosing, the pattern ofthe drug concentration cycle is repeated identically in each intervalbetween doses with the mean concentration remaining constant. In thecase of constant infusion, the mean drug concentration will remainconstant with very little oscillation. The achievement of steady stateis determined by means of measuring the concentration of drug in plasmaover at least one cycle of dosing such that one can verify that thecycle is being repeated identically from dose to dose. Typically, in anintermittent dosing regimen, maintenance of steady state can be verifiedby determining drug concentrations at the consecutive troughs of acycle, just prior to administration of another dose. In a constantinfusion regimen where oscillation in the concentration is low, steadystate can be verified by any two consecutive measurements of drugconcentration.

FIG. 7 shows a kit according to the invention. The kit 10 includes avial 12 containing opioid tablets. The kit 10 also includes a vial 14containing S-MNTX tablets which comprise pellets, some of which areenterically coated with pH sensitive material and some of which areconstructed and arranged to release the S-MNTX immediately in thestomach. The kit also includes instructions 20 for administering thetablets to a subject who has diarrhea or who has symptoms of diarrhea.The instructions include indicia, for example writing, indicating thatthe S-MNTX is pure S-MNTX free of R-MNTX.

In some aspects of the invention, the kit 10 can include optionally oralternatively a pharmaceutical preparation vial 16 and a pharmaceuticalpreparation diluent vial 18. The vial containing the diluent for thepharmaceutical preparation is optional. The diluent vial contains adiluent such as physiological saline for diluting what could be aconcentrated solution or lyophilized powder of S-MNTX. The instructionscan include instructions for mixing a particular amount of the diluentwith a particular amount of the concentrated pharmaceutical preparation,whereby a final formulation for injection or infusion is prepared. Theinstructions 20 can include instructions for treating a patient with aneffective amount of S-MNTX. It also will be understood that thecontainers containing the preparations, whether the container is abottle, a vial with a septum, an ampoule with a septum, an infusion bag,and the like, can contain additional indicia such as conventionalmarkings which change color when the preparation has been autoclaved orotherwise sterilized.

This invention is not limited in its application to the details ofconstruction and the arrangement of components set forth in thefollowing description or illustrated in the drawings. The invention iscapable of other embodiments and of being practiced or of being carriedout in various ways. Also, the phraseology and terminology used hereinis for the purpose of description and should not be regarded aslimiting. The use of “including,” “comprising,” or “having,”“containing”, “involving”, and variations thereof herein, is meant toencompass the items listed thereafter and equivalents thereof as well asadditional items.

EXAMPLES

A number of different synthetic pathways and protocols were attempted tofind an efficient method for the production and purification of S-MNTX.A description of some of these are provided below. Also provided areprocedures for producing reagents, intermediates and starting materials.

Example I

Deprotection of Oxycodone to Oxymorphone. Oxymorphone was synthesizedfrom oxycodone. The deprotection of oxycodone to oxymorphone was doneusing conditions previously described in the literature. (Iijima, I.;Minamikawa, J.; Jacobson, A. E.; Brossi, A.; Rice, K. C. J. Med. Chem.1978, 21(4), 398.) Yields ranged from 58-64% with purificationconsisting of filtration through a short plug of silica gel to removebaseline material. Purified oxymorphone was used for the alkylationreactions. Yields of oxymorphone up to 95% were obtained withoutpurification. HPLC purities of this crude material were typically about94%.

Preparation of (Iodomethyl)cyclopropane. (Iodomethyl)cyclopropane wasprepared from (bromomethyl)cyclopropane through a Finkelstein reaction.Typical yields ranged from 68-70% and typical purities were 89-95% (AUC)by GC, with the starting bromide as the only major impurity.

Direct Alkylation of Oxymorphone. Direct alkylation of oxymorphone withcyclopropylmethyliodide as the alkylating agent proved to giveproductive yields of S-MNTX. The pathway is illustrated in FIG. 2. Thedirect alkylation of oxymorphone was observed to proceed to nearly 50%conversion as observed by HPLC (AUC), and was investigated further.

Oxymorphone was combined with cyclopropylmethyl iodide in NMP (10 vol)and heated to 70° C. The results are summarized below in Table 1. Thedecomposition of the alkylating agent did not completely consume thereagent during the reaction time and thus was not limiting the reactionfrom proceeding to completion. In addition, the ratio of oxymorphone toS-MNTX showed that the reaction proceeded to nearly 1:1 regardless ofthe number of equivalents of alkylating agent.

TABLE 1 Investigation Into the Effect of the Equivalents of AlkylatingAgent Used Reaction Composition After 16 Hours at 70° C. Alkyl Iodide(HPLC, AUC) Entry (Equiv) % Oxymorphone % S-MNTX % Alkyl Iodide 1 8 3330 16 2 12 29 27 25 3 16 27 23 35 4 20 23 20 42 5 24 22 18 44

Work up procedure. Since the presence of NMP in the crude product wasfound to prevent retention, a means of removing it was required. Amixture of isopropyl acetate and dioxane formed a flocculent, a lightcolored solid that eventually became an oil. The use of isopropylacetate and the mixture of isopropyl acetate/dioxane were compared todetermine which was more effective at removing the NMP. In each case,the product and starting material were precipitated from the mixture andNMP remained in solution. Analysis of the supernatant liquid and theprecipitated material by HPLC showed no significant difference betweenthe two.

Purification. Once the NMP was removed from the product, the residue wassubjected to repetitive sequential reverse-phase chromatography usingBiotage Flash chromatography systems, equipped with C18 cartridges.Initial chromatography was carried out using 50% aqueous methanolcontaining 0.2% HBr as a modifier. The solvent system was incrementallyreduced in methanol content until 5% aqueous methanol was settled upon.The chromatography was repeated until S-MNTX was isolated at a purity of89% (AUC). The counterion was not detectable by MS, but was expected tobe a mixture of iodide and bromide.

With the workup and purification defined, the chemistry was scaled upand 28 g of oxycodone·HCl was carried through the process. The firststep, demethylation, was carried out in one reaction using the proceduredescribed in the literature and afforded 17 g of oxymorphone, afterrecrystallization from hot ethanol (10 volumes). The second step wascarried out in five equal smaller reactions because of equipmentlimitations resulting from the size and mode of heating of the pressuretubes. Although analyzed separately, the mixtures were combined for theworkup and purification after analysis indicated similar composition.The isopropyl acetate trituration proceeded as expected and theprecipitated residue was dissolved into 20% aqueous methanol containing0.2% HBr and was purified by chromatography on a Biotage Flash 40s,equipped with a C18 cartridge and eluted with 5% aqueous methanolcontaining 0.2% HBr. The fractions were analyzed by HPLC and thefractions of similar composition were combined, separated into <80%,80-90%, and <90% purities (AUC). The combined fractions wereconcentrated and rechromatographed on a Biotage Flash 75L, equipped witha C18 cartridge. This chromatographic procedure was repeated to enhancethe purity. Eventually it was discovered that the HBr modifier wasunnecessary and was removed from the eluent. After six chromatographicpurifications, nearly 11 g of S-MNTX iodide was isolated atapproximately 80% purity (AUC).

It became apparent that during the concentration of the fractions thatsome form of decomposition was occurring and resulted in a significantdarkening of the product. The decomposition was attributed to the iodidecounterion and, thus, the material was passed through an anion-exchangecolumn to exchange the iodide for bromide. Once the eluent containingproduct was collected, concentration did not appear to result in thefamiliar darkening and afforded a yellow oil. The chromatography wascontinued, separating the product streams by purity level (AUC by HPLC).Once the bulk of the material had been enhanced to approximately 90%purity, additional chromatography was carried out using 2.5% aqueousmethanol as the eluent and eventually improved the purity of somematerial to >95% (AUC).

All the product streams were combined and lyophilized to affordfree-flowing powders, 741 mg of S-MNTX was isolated at 95% pure, 2.5 gof S-MNTX was isolated at 90% purity, and 1.0 g of S-MNTX was isolatedat 79% purity (AUC). The fractions of recovered oxymorphone werecollected and recrystallized from ethanol to afford 2.4.g (>99% purity,AUC).

Reagent Preparation. In a series of experiments directed to producingS-MNTX, starting materials and reagents were obtained or made asdescribed below. Equipment and instrumentation data are also provided.

Alliionaqueous reactions were performed under dry nitrogen. Unlessotherwise noted, reagents were purchased from commercial sources andused as received. Proton nuclear magnetic resonance spectra wereobtained on a Bruker Avance 300 spectrometer at 300 MHz withtetramethylsilane used as an internal reference. Carbon nuclear magneticresonance spectra were obtained on a Bruker Avance 300 Spectrometer at75 MHz with the solvent peak used as the reference. Infrared spectrawere obtained on a Perkin-Elmer Spectrum 1000 spectrophotometer. Massspectra were obtained on a Finnigan mass spectrometer.

Thin layer chromatography (TLC) was performed using 2.5×10 cm AnaltechSilica Gel GF plates (25 microns thick). Visualization of TLC plates wasperformed using UV and potassium permanganate stain. HPLC analysis wasperformed on a Varian ProStar HPLC controlled by Varian Star softwareusing the following method:

HPLC Method I:

-   Column: Luna C18(2), 150×4.6 mm, 5μ-   Flow Rate: 1 mL/min-   Detection: UV @ 230 nm-   Gradient Program:

Time (min) % A % B  0:00 95 5  8:00 65 35 12:00 35 65 15:00 0 100 16:0095 5 18:00 95 5 Mobile phase A = 0.1% Aqueous TFA Mobile phase B = 0.1%Methanolic TFA

HPLC Method II:

-   Chromatographic Conditions and Parameters: Analytical Column    Description:-   Phenomenex Inertsil ODS-3 150×4.6 mm, 5 μm Column Temperature:    50.0° C. Flow-   Rate: 1.5 mL/min Injection Volume: 20 μL Detection Wavelength: 280    nm Mobile-   Phase: A=Water: MeOH: TFA (95:5:0.1%; v/v/v) B=Water: MeOH: TFA    (35:65:0.1%; v/v/v) Analysis Time: 50 min-   Quantitation limit: 0.05%-   Detection limit: 0.02%

Gradient Profile:

Time (min) % A % B Curve 0:00 100 0 Initial 45 50 50 Linear 48 100 0Linear 55 100 0 Hold Mobile Phase A (Water:MeOH:TFA :: 95:5:0.1%, v/v/v)Mobile Phase B (Water:MeOH:TFA :: 35:65:0.1%, v/v/v) MeOH = Methanol TFA= trifluoroacetic acid

The synthesis and purification of S-MNTX were monitored using the aboveHPLC protocol. S-MNTX is distinguished from R-MNTX using the HPLCconditions described. Authentic R-MNTX for use as a standard may be madeusing the protocol described herein. In a typical HPLC run, S-MNTXelutes about 0.5 minutes before 8-MNTX elutes. The retention time ofS-MNTX is approximately 9.3 minutes; the retention time of R-MNTX isabout 9.8 minutes.

Gas chromatographic (GC) analysis was performed on an HP 5890 Series IIGC controlled by HP 3365 ChemStation software using the followingmethod:GC Method:

-   Column: J&W Scientific DB-1, 30 m×0.53 mm, 3μ-   Initial Temp: 40° C.-   Initial Time: 10.00 min-   Rate: 20° C./min-   Final Temp: 250° C.-   Final Time: 2.00 min-   Injector Temp: 250° C.-   Detector: Flame-Ionization

Typical Alkylation Reaction. The substrate was charged to a 250-mL Parrflask along with 10 volumes alkylating agent. If dimethyl formamide(DMF) or NMP was used as a cosolvent, 2.5 volumes were added. The flaskwas placed in a Parr shaker (hydrogen tank closed off) and heated to thereaction temperature with shaking under pressure. Pressures typicallyseen during the reaction were 10-15 psi. The reaction was periodicallysampled and analyzed by MS and HPLC to determine the extent of reactionand the nature of the products. At the end of the reaction, the mixturewas transferred to a round-bottom flask with methanol and the volatilesremoved. The residue was then chromatographed on silica gel eluting with90:10:0.1 methylene chloride/methanol/ammonium hydroxide.

Preparation of the Ion-Exchange Column. AG 1-X8 resin (Bio-Rad,analytical grade, 100-200 mesh, chloride form) was packed into a glasscolumn (50 mm×200 mm) and was washed with 1 N HBr (1 L, prepared withdeionized (DI) water). The column was washed with DI water(approximately 10 L) until the eluent reached a pH of 6-7.

Preparation of S-MNTX. Into five, 25-mL threaded closure pressure tubeswere combined oxymorphone (3.6 g, 11.9 mmol), cyclopropylmethyl iodide(17.39 g, 95.6 mmol), and N-methyl pyrrolidone (3.6 mL). The tubes weresealed with threaded Teflon caps and placed into a 6-well reactor block,preheated to 70° C. After 24 h, the reactions were visibly biphasic andHPLC analysis, sampling both solid and liquid phases, showed that thereactions proceeded to approximately 50% conversion. Heating wasdiscontinued and the five reaction mixtures were transferred to a 1-L,round-bottom flask using methanol to transfer the mixtures and rinse thetubes. The methanol was removed under reduced pressure and the resultingNMP solution was treated with isopropyl acetate (900 mL), which resultedin both solid and oily precipitates. The oil was agitated with a spatulato afford a sticky solid. The supernatant liquid was decanted from thesolid into a fluted filter paper. The solid collected in the filterpaper was combined with the original solid, using methanol to aid in therecovery. The resulting solution was concentrated to a dark, viscousoil. The oil was dissolved into 20% aqueous methanol containing 0.2% HBr(20 mL) and was purified by chromatography on a Biotage Flash 75Lequipped with a C18 cartridge. The fractions were analyzed by HPLC on aLuna C18(2) column (4×20 mm) and the product fractions were combined andconcentrated. The resulting “purified” product dissolved into DI water(approximately 20 mL) and the chromatography was repeated with theprocess being repeated until the purity was enhanced to approximately70% (AUC). The approximately 70% pure product (approximately 18 g) wasdissolved into DI water (20 mL) and passed through a column of AG 1-X8anion-exchange resin converted to the bromide form (see additionalprocedure) (5×25 cm). The column was eluted with DI water until no MNTXwas detectable in the eluted stream. The aqueous solution wasconcentrated and the residue was dissolved into DI water (10 mL), whichwas purified by chromatography further using the Biotage Flash 75Lsystem equipped with a C18 cartridge and eluted with 5% aqueousmethanol. The fractions were analyzed by HPLC on a Luna C18(2)column(4.6×150 mm) and the product stream was partitioned into fourstreams based on purity (AUC); >90%, 50-90% with fast impurities, 50-90%with slow impurities, and <50%. The less-pure material was recycledthrough the chromatography to enhance the purity, which ultimatelyresulted in 3.0 g of S-MNTX that was 90% pure (AUC). The less-purefractions were purified by chromatography further to provideapproximately 1 g of 90% pure material, which was combined with 1.0 g ofthe 90% pure material previously isolated and purified by chromatographyon a Biotage Flash 75L equipped with a C18 cartridge and eluted with2.5% aqueous methanol. The chromatography was repeated to enhance thepurity until >95% (AUC) was achieved. At the conclusion, the productstreams were lyophilized from water to afford 741 mg of S-MNTX at 95.6%purity (AUC); 2.54 g of S-MNTX at 90% purity (AUC); and L08 g of S-MNTXat 79% purity (AUC).

FIG. 3 provides a proton NMR spectrum of S-MNTX produced by this method.FIG. 4 provides an infrared spectrum of the S-MNTX product. FIG. 5provides an HPLC chromatogram of the S-MNTX product. FIG. 6 provides amass spectrogram of the S-MNTX product. These analytical data identifythe “S” stereoisomer of MNTX at a purity of greater than 95%.

Example II Optimization of the Synthesis and Purification of S-MNTX

Preparation of the Ion-Exchange Column. AG 1-X8 Resin (Bio-Rad,analytical grade, 100-200 mesh, chloride form, 50 wt equiv) was packedinto a glass column and was washed with 1 N HBr (approximately 100 vol,prepared with DI water). The column was washed with DI water until theeluent reached a pH of 6-7.

Preparation of S-MNTX. A 250-mL, jacketed, three-neck flask was chargedwith oxymorphone (5.0 g, 16.6 mmol), NMP (5 mL) and copper wire (1.2 g,cut into 3-4 mm pieces). The flask was wrapped in aluminum foil and wasconnected to a pre-equilibrated heater/chiller set at 70° C.Cyclopropylmethyl iodide (24.16 g, 132.7 mmol) was added to the mixtureand the reaction was stirred for 20 h. Analysis of a reaction aliquot byHPLC revealed a 1:1 ratio of 2:3. The reaction mixture was transferredinto an Erlenmeyer flask containing IPAc (250 mL) that was vigorouslystirred with an overhead mechanical stirrer. After the oily materialsolidified, the solid was filtered off and was transferred back into theflask; the filtrate was analyzed by HPLC and was discarded. The combinedsolid residues were dissolved in aqueous methanol and were filteredthrough a column of ion-exchange resin (Bio-Rad AG 1-X8, 50 wt equiv,converted to bromide form). The column was eluted with DI water and wasrinsed until no UV active material was detected (254 nm). The resultingaqueous solution was concentrated and the residue was dissolved in IPA(5 vol) with a minimum amount of methanol to achieve solution. Thesolvent was stripped to remove traces of water and the resulting solidwas dissolved in hot methanol (3 vol at approximately 50° C.). Anambient temperature mixture of methylene chloride/isopropyl alcohol(CH₂Cl₂/IPA) (6 vol/1 vol) was added and the resulting solution wasallowed to stand under ambient conditions until crystallization began.The mixture was then kept in a −20° C. freezer for 2 days. The solid wascollected by filtration and afforded 2.8 g of a nearly 1:1 mixture of 2and S-MNTX. The solid was recrystallized from hot methanol (MeOH) (3 volat approximately 50° C.) by adding CH₂Cl₂/IPA (6 vol/1 vol), andallowing the mixture to cool. The isolated solid (2.1 g, 29% based onweight) was found to be 94.1% pure (AUC) by HPLC analysis.

Purification of S-MNTX. The lots of S-MNTX of purity >94% (AUC) werecombined and carried through the recrystallization procedure ofdissolving in hot methanol (3 vol at approximately 50° C.) and thenadding a CH₂Cl₂/IPA (6 vol/1 vol) mixture. The mixture was allowed tocool to ambient temperature and the solid was collected by filtration.Four iterations were required to improve the purity of S-MNTX from 94%to >99% and the overall mass recovery was 60%. In total, 8.80 g ofS-MNTX were purified to 99.8% (AUC) as determined by HPLC analysis. The¹H NMR, ¹³C NMR, and MS spectra were consistent with the assignedstructure. Karl Fischer Analysis (KF): 4.7% water; Anal. Calcd forC₂₁H₂₆BrNO₄: C, 57.80; H, 6.01; N, 3.21; Br, 18.31. Found: C, 54.58; H,6.10; N, 2.82; Br, 16.37.

Example III Opiate Receptor Binding of (S)-N-methylnaltrexone

Radioligand binding assays were conducted to determine the bindingspecificity of S-N-methynaltrexone for μ-, κ-, and δ-opiate receptorsusing methods adapted from scientific literature (Simonin, F et al 1994,Mol. Pharmacol 46:1015-1021; Maguire, P. et al 1992, Eur. J. Pharmacol.213:219-225; Simonin, F. et al PNAS USA 92(15):1431-1437; Wang, J B1994, FEBS Lett 338:217-222).

S-MNTX was shown to bind human recombinant mu opioid receptors with aKi=0.198 μM; to bind human recombinant kappa opioid receptors withKi=1.76 μM, and did not bind to human recombinant delta opioidreceptors.

Example IV In Vitro Pharmacology of S-MNTX: μ (mu, MOP) ReceptorBioassay

Experimental Conditions. Segments of guinea pig terminal ileum weresuspended in 20-ml organ baths filled with an oxygenated (95% O₂ and 5%CO₂) and pre-warmed (37° C.) physiological salt solution of thefollowing composition (in mM): NaCl 118.0, KCl 4.7, MgSO₄ 1.2, CaCl₂2.5, KH₂PO₄ 1.2, NaHCO₃ 25.0 and glucose 11.0 (pH 7.4). Additionalexperimental conditions were as described in Hutchinson et al. (1975)Brit. J. Pharmacol., 55: 541-546.

Indomethacin (1 μM), nor-binaltorphimine (0.01 μM), methysergide (1 μM),ondansetron (10 μM) and GR1 13808 (0.1 μM) were also present throughoutthe experiments to prevent prostanoid release and to block the k-opioid,5-HT2, 5-HT3 and 5-HT4 receptors, respectively. The tissues wereconnected to force transducers for isometric tension recordings. Theywere stretched to a resting tension of 1 g then allowed to equilibratefor 60 min during which time they were washed repeatedly and the tensionreadjusted. Thereafter, they were stimulated electrically with pulses ofminimal intensity to to trigger maximal contractions and 1 ms duration,delivered at 0.1 Hz by a constant current stimulator. The experimentswere carried out using a semi-automated isolated organ system possessingeight organ baths, with multichannel data acquisition.

Experimental Protocols

Test for agonist activity. The tissues were exposed to a submaximalconcentration of the reference agonist DAMGO (0.1 μM) to verifyresponsiveness and to obtain a control response. Following extensivewashings and recovery of the control twitch contractions, the tissueswere exposed to increasing concentrations of S-MNTX or the same agonist.The different concentrations were added cumulatively and each was leftin contact with the tissues until a stable response was obtained or fora maximum of 15 min. If an agonist-like response (inhibition of twitchcontractions) was obtained, the reference antagonist naloxone (0.1 μM)was tested against the highest concentration of S-MNTX to confirm theinvolvement of the μ receptors in this response.

Test for antagonist activity. The tissues were exposed to a submaximalconcentration of the reference agonist DAMGO (0.1 μM) to obtain acontrol response. After stabilization of the DAMGO-induced response,increasing concentrations of S-MNTX or the reference antagonist naloxonewere added cumulatively. Each concentration was left in contact with thetissues until a stable response was obtained or for a maximum of 15 min.If it occurred, an inhibition of the DAMGO-induced response by S-MNTXindicated an antagonist activity at the μ receptors.

Analysis and Expression of Results. The parameter measured was themaximum change in the amplitude of the electrically-evoked twitchcontractions induced by each compound concentration. The results areexpressed as a percent of the control response to DAMGO (mean values).The EC₅₀ value (concentration producing a half-maximum response) or IC₅₀value (concentration causing a half-maximum inhibition of the responseto DAMGO) were determined by linear regression analysis of theconcentration-response curves.

Results. The effects of S-MNTX investigated from 1.0E-08 M to 1.0E-04 Mfor agonist and antagonist activities at the μ-opioid receptors in theguinea pig ileum bioassay are presented in Table IV.1 where those of thereference compounds are also reported. The EC₅₀ and IC₅₀ valuesdetermined for S-MNTX are indicated in Table IV.2.

In the field-stimulated guinea pig ileum, the μ receptor agonist DAMGOinduced a concentration-dependent decrease in the twitch contractionamplitude which was reversed by the antagonist naloxone in aconcentration-dependent manner.

In the untreated tissues, S-MNTX also caused a concentration-dependentand naloxone-sensitive decrease in the twitch contraction amplitude. Inthe tissues previously depressed with DAMGO, S-MNTX did not produce anyrecovery of the twitch contraction amplitude but caused a furtherdecrease.

These results indicate that S-MNTX behaves as an agonist at the μ-opioidreceptors in this tissue.

TABLE IV.1 Effects of S-MNTX evaluated for agonist and antagonistactivities at the μ-opioid receptors in the guinea pig ileum Evaluationof agonist activity Control response Responses to + to DAMGO increasingconcentrations of the naloxone Compounds (1.0E−07M) compounds (M)(1.0E−07M) 1.0E−08 3.0E−08 1.0E−07 3.0E−07 1.0E−06 3.0E−06 1.0E−053.0E−05 1.0E−04 1.0E−04M S-MNTX 100 0 0 5 16 35 59 92 109 109 17 1.0E−091.0E−08 1.0E−07 1.0E−07 DAMGO 100 12 49 99 3 Evaluation of antagonistactivity Control response to DAMGO Responses to DAMGO (1.0E−07M) in thepresence of Compounds (1.0E−07M) increasing concentrations of thecompounds (M) 1.0E−08 3.0E−08 1.0E−07 3.0E−07 1.0E−06 3.0E−06 1.0E−053.0E−05 1.0E−04 S-MNTX 100 100 100 100 100 100 102 105 109 110 5.0E−092.0E−08 1.0E−07 naloxone 100 83 43 −7 The results are expressed as apercent of the control response to DAMGO (decrease in twitch contractionamplitude) (mean values; n = 2)

TABLE IV. 2 EC₅₀ and IC₅₀ values determined for S-MNTX at the μ-opioidreceptors in the guinea pig ileum Agonist activity Antagonist activityCompound EC₅₀ value IC₅₀ value S-MNTX 2.0E−06 M No antagonist activity

Example V Effect of S-N-Methylnaltrexone on Gastrointestinal Transit inRats

The effect of S-N-methylnaltrexone (purity-99.81% S-N-methylnaltrexone;0.19% oxymorphone; no detectable R-MNTX), as well as an authentic sourceof R-MNTX (purity 99.9%), on morphine-induced inhibition ofgastrointestinal transit in rats was determined using methods describedin A. F. Green, Br. J. Pharmacol. 14: 26-34, 1959; L. B. Witkin, C. F.et al J. Pharmacol. Exptl. Therap. 133: 400-408, 1961; D. E. Gmerek, etal J. Pharmacol. Exptl. Ther. 236: 8-13, 1986; and 0. Yamamoto et alNeurogastroenterol. Motil. 10: 523-532, 1998.

S-MNTX or R-MNTX was administered subcutaneously to rats (Crl:CD®(SD)BR;5-8 wks old; 180-250 gms wt) at concentrations of 1.0, 3.0, or 10.0mg/kg. A control group of rats received 2 mL/kg of a 0.9% salinesolution (n=10). After 15 minutes, rats were subcutaneously injectedwith saline (1mL/kg) or morphine (3 mg/kg). A 10% suspension ofactivated charcoal in 0.25% methylcellulose was administered orally at10 mL/kg to the rats 20 minutes (±2 minutes) after the subcutaneous doseof morphine or saline. The rats were euthanized 25 minutes (±3 minutes)after receiving the charcoal and the intestines were removed and lightlystretched on moist paper along a meterstick. The small intestine frompyloric sphincter to caecum was measured and the distance traveled bythe charcoal as a fraction of that length was evaluated for each rat.

Statistically significant effects were determined by ANOVA with TukeyHSD Multiple Comparison Test. Differences with p values <0.05 wereconsidered statistically significant.

Values for charcoal motility were expressed as a percent effect and werecalculated in the following manner: The individual distance traveled bythe charcoal in centimeters was divided by the total length of theintestines in centimeters (pyloric sphincter to caecum) for each rat.Mean values were calculated for each group, and the percent effect wascalculated using the following formula:

${\% \mspace{14mu} {Effect}} = {\frac{\left( {{Mean}\mspace{14mu} {value}\mspace{14mu} {for}\mspace{14mu} {controls}} \right) - \left( {{Mean}\mspace{14mu} {value}\mspace{14mu} {for}\mspace{14mu} {treated}} \right)}{{Mean}\mspace{14mu} {value}\mspace{14mu} {for}\mspace{14mu} {controls}} \times 100}$

Results

The results from the GI transit study are shown in Table 1. Morphine,known to affect both central and peripheral opioid receptors, decreasedGI motility as reported in the literature. R-MNTX, a peripherallyselective mu opioid receptor antagonist, had no effect on GI transitwhen administered alone. R-MNTX administered prior to morphine reversedthe GI slowing effect of morphine as would be expected from an opioidantagonist. The antagonist activity of R-MNTX on morphine wasdose-dependent, with a partial reversal at 1 mg/kg and reversal at 3 or10 mg/kg to the degree that GI transit was returned to values that werenot statistically significantly different from the control value. Incontrast to the antagonist activity of R-MNTX, S-MNTX had agonistactivity when used alone, i.e. it resulted in decreased GI motility asreflected in a statistically significantly decrease in GI transit. Theagonist activity of S-MNTX in decreasing GI motility was even morepronounced using S-MNTX and morphine in combination. The combination ofS-MNTX +morphine had a dramatic synergistic agonist effect in decreasingGI motility to levels not observed using either compound alone. Theagonist activity of S-MNTX was manifested as a slowing of GI transitwhen it was administered by itself and also by the increase in theinhibitory effect of morphine when the two agents were used incombination.

TABLE 1 Effect of S-MNTX on GI Motility Mean Percent Treatment MotilityDecrease Saline + Saline 0.606 — Saline + Morphine 0.407* 33% R-MNTX 10mg/kg + Saline 0.572  6% R-MNTX 1 mg/kg + Morphine 0.463* 24% R-MNTX 3mg/kg + Morphine 0.558  8% R-MNTX 10 mg/kg + Morphine 0.557  8% S-MNTX10 mg/kg + Saline 0.476* 21% S-MNTX 1 mg/kg + Morphine 0.281* 54% S-MNTX3 mg/kg + Morphine 0.258* 57% S-MNTX 10 mg/kg + Morphine 0.122* 80%Route—sc Morphine dose = 3 mg/kg Mean Motility—ratio of length ofcharcoal transit/total intestine length *Statistically significant (p <0.05) change when compared to the vehicle group

Example VI Tests for Anti-Diarrheal Activity

-   -   (a) Castor Oil Test in Rats [see, e.g., Niemegeers et al. (1972)        Arzneim Forsch 22:516-518; U.S. Pat. Nos. 4,867,979; 4,990,521;        4,824,853]

Rats are fasted overnight. Each animal is treated intravenously with thedesired dose of the compound to be tested. One hour thereafter, theanimal receives 1 ml of castor oil orally. Each animal is kept in anindividual cage and about 2 hours after the castor oil treatment, eachanimal is assessed for the presence or absence of diarrhea. The ED₅₀value is determined as that dose in mg/kg body weight at which nodiarrhea is present in 50% of the tested animals.

For example, young female Wistar rats (230-250 g body weight) are fastedto overnight and in the morning each animal is treated orally with adose level of the compound to be tested. One hour thereafter, the animalreceives 1 ml of castor oil orally. Each animal is kept in an individualcage. At different selected time intervals (e.g., 1, 2, 3, 4, 6 and 8hrs) after the castor oil treatment, the presence or absence of diarrheais noted. In more than 95% of 500 control animals, severe diarrhea isobserved 1 hour after treatment with castor oil. Using this all-or-nonecriterion, a significant positive effect occurs with the tested compoundif no diarrhea is observed 1 hour after the castor oil treatment. Aminimum of 5 dose levels are used per drug, each dose level being givento 10 rats on ten different days. The ED₅₀ value, i.e., the dose levelat which such effect is observed in 50% of the animals, for thecompounds, such as the compounds of formula (II), generally ranges fromabout 0.01 to about 10 mg/kg.

-   -   (b) Castor Oil Test in Mice [See, e.g., U.S. Pat. No. 4,326,075]

Groups of mice are orally dosed with test compound and one-half hourlater all mice are given 0.3 ml of castor oil. Three hours after castoroil administration, all of the mice are checked for diarrhea and thedose of testing compound which protected 50% of the mice from diarrheais the ED₅₀ dose.

-   -   (c) Ricinus Oil Test [See, e.g., U.S. Pat. No. 4,990,521]

Rats, such as female Wistar rats or other laboratory strains, are fastedovernight. Each animal is treated orally with a dose level of the testcompound. One hour thereafter, the animal is given an amount, typically1 ml, of ricinus oil orally, each animal is kept in an individual cageand 1 hour after the ricinus oil treatment, the presence or absence ofdiarrhea is noted. The ED₅₀ value is determined as that dose in mg/kgbody weight at which no diarrhea is present in 50% of the treatedanimals.

-   -   (d) Antagonism of PGE₂-induced Diarrhea in Mice

Anti-diarrheal activity can be determined by assessing the effects of acompound as an antagonist of PGE₂-induced diarrhea in mice [see, e.g.,Dajani et al. 1 975) European Jour. Pharmacol. 34:105-113; and Dajani etal. (1977) J. Pharmacol. Exp. Ther. 203:512-526; see, e.g., U.S. Pat.No. 4,870,084]. This method reliably elicits diarrhea in otherwiseuntreated mice within 15 minutes. Animals that are pretreated with thetest agent in which no diarrhea occurs are considered protected by thetest agent. The constipating effects of test agents are measured as an“all or none” response, and diarrhea is defined as watery unformedstools, very different from normal fecal matter, which has well-formedboluses, and is firm and relatively dry.

Standard laboratory mice, such as albino mice of the Charles River CD-1strain, are used. They are typically kept in group cages. The weightrange of the animals when tested is between 20-25 g. Pelleted rat chowis available ad libitum until 18 hours prior to testing, at which timefood is withdrawn. Animals are weighed and marked for identification.Five animals are normally used in each drug treatment group and comparedwith controls. Mice weighing 20-25 g are housed in group cages, andfasted overnight prior to testing. Water is available. Animals arechallenged with PGE₂ [0.32 mg/kg i.p. in 5% ETOH] one hour after testdrug treatment, and immediately placed individually, for example, intransparent acrylic boxes. A disposable cardboard sheet on the bottom ofthe box is checked for diarrhea on an all or nothing basis at the end of15 minutes.

Example VII Analgesic Activity of S-MNTX in Pain Models

The following pain models are useful in determining the analgesicactivity of S-MNTX.

1. Acetic Acid Writhing assay in Mice

Mice (CD-1, male) are weighed and placed in individual squares. The testor control article are administered and after the appropriate absorptiontime, acetic acid solution are administered intraperitoneally. Tenminutes after the i.p. injection of acetic acid, the number of writhesare recorded for a period of 5 minutes.

The total number of writhes for each mouse are recorded. The mean numberof writhes for the control and each test article group are comparedusing an ANOVA followed by a relevant multiple comparison test andpercent inhibition calculated.

2. Phenylquinone (PPQ) Writhing Assay

Mice (CD-1, male) are weighed and placed in individual squares. The testor control article are administered and after the appropriate absorptiontime, the PPQ solution (0.02% aqueous solution) is administeredintraperitoneally. Each animal is observed closely for ten minutes forexhibition of writhing.

The total number of writhes for each mouse are recorded. The mean numberof writhes for the control and each test article group are comparedusing an ANOVA followed by a relevant multiple comparison test andpercent inhibition calculated.

3. Randall-Selitto Assay in Rats

The purpose of this assay is to determine the effect of test articlesupon the pain threshold of rats.

Following an overnight fast, rats are placed in groups of ten. Twentyrats are used as vehicle controls. The rats are then sequentiallyinjected with a 20% Brewer's yeast suspension into the plantar surfaceof the left hind paw. Two hours later the rats are administered the testarticle, reference drug, or control vehicle. One hour after doseadministration, the pain threshold of the inflamed and non-inflamed pawis measured by a “Analgesia Meter” that exerts a force which increasesat a constant rate along a linear scale.

The control group threshold and standard deviation for the inflamed pawand non-inflamed paw are calculated. Rats in the test article group andreference group are considered protected if the individual painthreshold exceeds the control group mean threshold by two standarddeviations of the means.

4. Hot Plate Analgesia Assay

Each mouse (CD-1, male) serves as its own control throughout theexperiment. The mice are placed sequentially on a Hot Plate AnalgesiaMeter (set for 55° C.±2° C.).

The mice react characteristically to the heat stimulus by:

1. Licking the forepaw 2. Rapid fanning of the hind paw 3. A sudden jumpoff the hot plate

Any of the three types of reactions are taken as an end point to theheat stimulus.

The mouse is removed from the hot plate immediately upon displaying theend point. The reaction time is measured quantitatively by the number ofseconds that elapse between the placing of the mouse on the hot plateand the display of a definitive end point. Elapsed time is measured by astop watch accurate to at least ⅕ of a second. Only mice whose controlreaction time is 10.0 seconds or less are used. At 15, 30, 60 and 120minutes (±1 to 5 minutes) after test or control article administration,reaction times will be obtained and recorded for the group sequentially.

Analgesic response is an increase in reaction time of the mouse to theheat stimulus. Percent analgesia is calculated from the average responseof the group of ten mice per dose level at a specified time interval:

${\% \mspace{14mu} {analgesia}} = {\frac{{average}\mspace{14mu} {response}\mspace{14mu} {time}\mspace{14mu} {in}\mspace{14mu} {seconds}\mspace{14mu} \left( {{test}\mspace{14mu} {article}\mspace{14mu} {treated}} \right)}{{average}\mspace{14mu} {response}\mspace{14mu} {time}\mspace{14mu} {in}\mspace{14mu} {seconds}\mspace{14mu} ({control})} - {1.0 \times 100}}$

An ANOVA with appropriate Multiple Comparison Test is then performed.

5. Rat Tail Radiant Heat Test (Tail. Flick)

To evaluate the potential ability of a test article to produce ananalgesic response to thermal stimulation in rats.

-   Following an overnight fast, rats are weighed and placed in groups    of ten. The test or vehicle control articles are administered. A    Tail Flick Analgesia Meter is used. Sixty minutes following oral    administration (or as recommended by the Sponsor), the tail of each    rat is exposed to a specific intensity of heat stimulus and the time    required to elicit a response (a characteristic tail flick) is    recorded.-   Percent analgesia will be calculated using the mean control response    compared to the mean test article response.

Example VIII Identification of Compounds for Use as PeripheralAnti-Hyperalgesics

In general, the methods described above, are also useful for assessingperipheral anti-hyperalgesic activities of test compounds. Mostpreferred among the methods for assessing anti-hyperalgesic activity arethose described in Niemegeers et al. (1974) Drug Res. 24:1633-1636.

1. Assessment of Ratio [C] of the ED₅₀ Value [A] in a Test forAnti-diarrheal Activity, Such as the Castor Oil Test, to the ED₅₀ Value[B] in a Test of CNS Effects, Such as the Tail Withdrawal Test

The agents intended for use in the methods and compositions can beidentified by their activity as anti-diarrheals, and their lack of CNSeffects. In particular, the selected compound exhibits anti-hyperalgesicactivity in any of the standard models, discussed above, and,preferably, either (a) the ratio of these activities [B/A], as measuredin standard assays, is substantially greater or equal to [at least equalto, more preferably at least about 2-fold greater] than the ratio ofsuch activities for diphenoxylate; or (b) the activity of the compoundin an assay that measures CNS activity is substantially less [at leasttwo-fold, preferably 3-fold or more] than diphenoxylate.

Example IX In Vitro Pharmacology of S-MNTX: cAMP Assay in CHO CellsExpressing Human μ (mu, MOP) Receptor

The mu opioid receptor is G_(i) coupled, which works by inhibiting acAMP increase. Thus in these experiments, cellular cAMP was increased byaddition of 10 μM forskolin. Prior addition of DAMGO, or similaragonists, e.g. endomorphin-1, fentanyl, or morphine, inhibited thisforskolin-induced increase. The absence of agonist effect, produced aresult equivalent to forskolin alone. Therefore, increasing agonistconcentration decreased cAMP levels.

Antagonists, such as CTOP, naloxone and ciprodime inhibited the cAMPinhibition. Thus full antagonist effect was equivalent to forskolinwithout any addition of μ-opioid agonist. In these experiments,antagonist was added, then 30 μM DAMGO, then forskolin. Therefore,increasing antagonist concentration increased cAMP.

Experimental Protocol Assay Characteristics:

EC50 (DAMGO): 12 nM

cAMP production

(with forskolin & IBMX): 3.4 pmol/well

Inhibition (10 uM DAMGO): 90%

Materials and Methods:

Cell Source: Human recombinant/CHO cells

Reference Agonist: DAMGO

Reference Inhibitor: CTOP (see antagonist SAP)

Reference Curve: DAMGO (cell activation)

cAMP (EIA control curve)

Cells were grown to confluence in 96-well plates. Cells were washed andequilibrated in physiological buffer before analysis. 20 ul of drug, 100uM IBMX and 10uM forskolin were added and incubated for 25 minutes atroom temperature and then the reaction was stopped with the addition of0.1 N HCl. Extracted cAMP level was determined via competitive EIA assayutilizing alkaline phosphatase. Additional experimental conditions wereas described in Toll L., J Pharmacol Exp Ther. (1995) to 273(2): 721-7.

Results

Agonist Assay: S-MNTX demonstrated an agonist response with EC50 of 600nM. (6.0E-7M) as shown in Table IX.1. The agonist response was complete(not partial).

TABLE IX.1 log {M} conc S-MNTX SD DAMGO SD −4.0 3 6 −1 3 −4.5 −3 1 −5.04 9 2 5 −5.5 11 6 −6.0 32 7 1 6 −6.5 66 21 −7.0 70 17 2 6 −7.5 79 24−8.0 104 10 68 28 −9.0 86 5 63 10 −10.0 88 22 −11.0 105 13

Antagonist. Assay: S-MNTX showed no antagonist effect, as it isdemonstrated by the results presented in Table X. 2.

TABLE IX. 2 log {M} conc S-MNTX Range CTOP Range −4.0 −13 5 −4.5 −13 1−5.0 −9 3 91 11 −5.5 −8 7 −6.0 −1 17 109 11 −6.5 9 1 −7.0 5 7 48 3 −7.56 7 −8.0 4 6 1 1 −9.0 0 4 −10.0 −11.0 −1 1

The disclosures of all patents, patent applications and scientificpublications cited or referenced herein are incorporated by reference intheir entirety, including the co-pending US Patent Application No.: NotYet Assigned, titled: “SYNTHESIS OF (R)-N-METHYLNALTREXONE”, AttorneyDocket No. PO453.70119US01 filed on May 25, 2006. In case of conflictbetween documents incorprated by reference and the instant applicationthe instant application will control.

Having thus described several aspects of at least one embodiment of thisinvention, it is to be appreciated various alterations, modifications,and improvements will readily occur to those skilled in the art. Suchalterations, modifications, and improvements are intended to be part ofthis disclosure, and are intended to be within the spirit and scope ofthe invention. Accordingly, the foregoing description and drawings areby way of example only.

1. An isolated compound of the S configuration with respect to nitrogenof Formula I:

wherein X is a counterion.
 2. The isolated compound of claim 1, whereinthe counterion is a halide, bromide, iodide, sulfate, phosphate,nitrate, or anionic-charged organic species. 3-5. (canceled)
 6. Theisolated compound of claim 1, having at least 75%, 90% or 95% purity.7-12. (canceled)
 13. A composition comprising MNTX, wherein the MNTXpresent in the composition is greater than 10%, 30%, 50%, 75%, 90%, 95%,98% or 99% in S configuration with respect to nitrogen. 14-20.(canceled)
 21. The composition of claim 13, wherein the MNTX has acounterion that is a halide, iodide, bromide, sulfate, phosphate,nitrate, or anionic-charged organic species. 22-24. (canceled)
 25. Thecomposition of claim 13, wherein the composition is a solution or asolid.
 26. (canceled)
 27. A pharmaceutical composition comprising aneffective amount of the composition of claim 13, and a pharmaceuticallyacceptable carrier.
 28. The pharmaceutical composition of claim 27,further comprising a therapeutic agent other than MNTX. 29-46.(canceled)
 47. A method for synthesizing a salt of S-MNTX comprising:combining (iodomethyl) cyclopropane with oxymorphone in a first solventto produce an iodo salt of S-MNTX.
 48. The method of claim 47 furthercomprising, transferring the iodo salt S-MNTX to a second solvent; andexchanging iodide for a counterion other than iodide.
 49. The method ofclaim 47 further comprising, transferring the iodo salt of S-MNTX to asecond solvent, and exchanging iodide for bromide to produce a bromosalt of S-MNTX. 50-58. (canceled)
 59. A method for inhibiting diarrheain a subject comprising administering to a subject in need of suchtreatment the pharmaceutical composition of claim 27 in an amounteffective to treat or prevent the diarrhea. 60-61. (canceled)
 62. Amethod of reducing a rate or a volume of discharge from an ileostomy orcholostomy in a subject comprising administering to the subject in needof such reduction the pharmaceutical composition of claim 27 in anamount effective to reduce the rate or volume of discharge from theileostomy or cholostomy.
 63. (canceled)
 64. A method for inhibitinggastrointestinal motility in a subject in need of such treatmentcomprising administering to the subject a pharmaceutical composition ofclaim 27 in an amount effective to inhibit gastrointestinal motility inthe subject.
 65. (canceled)
 66. A method for treating irritable bowelsyndrome comprising administering to a patient in need of such treatmentthe pharmaceutical composition of claim 27, in an amount effective toameliorate at least one symptom of the irritable bowel syndrome.
 67. Amethod for inhibiting pain in a subject comprising administering thepharmaceutical composition of claim 27 in an amount sufficient toprevent or treat the pain. 68-76. (canceled)
 77. A method for inhibitinginflammation in a subject comprising administering to a subject in needthereof the pharmaceutical composition of claim 27 in an amounteffective to inhibit the inflammation. 78-82. (canceled)
 83. A method ofinhibiting production of tumor necrosis factor (TNF) in a subject,comprising: administering to the subject a composition comprising TNFproduction-inhibitory amount of a pharmaceutical composition of claim27. 84-91. (canceled)
 92. A method for regulating gastrointestinalfunction comprising administering to a subject in need thereof thepharmaceutical composition of claim 27, and administering to the subjecta peripheral mu opioid antagonist. 93-94. (canceled)
 95. A method formanufacturing S-MNTX comprising the following steps, (a) obtaining afirst composition containing S-MNTX, (b) purifying the first compositionby chromatography, recrystallization or a combination thereof, (c)conducting HPLC on a sample of purified first composition using S-MNTXas a standard, (d) determining the presence or absence of R-MNTX in thesample. 96-104. (canceled)